Air pollution: Delhi
This is a collection of articles archived for the excellence of their content.
Historical trends: Changes in pollution levels over the years:
2000-2015: University of Miami’s analysis
The Times of India Jan 07 2016
Air pollution has been increasing in and around Delhi since the year 2000 with just two blips between 2004 and 2006, a new analysis has revealed. This contradicts government agencies' claim that there is no definite trend of deteriorating air quality .
Using satellite measurements, an American scientist has found a steady increase in both PM2.5 (fine, respirable particles) and PM10 (coarse particles) in Delhi's air between 2000 and 2015, with the annual averages ranging from 74 to 92 micrograms per cubic metre.
Naresh Kumar, associate professor of environmental health at the University of Miami, USA, analysed satellitebased aerosol optical depth (AOD) in and around Delhi 2000 onwards, using data from Moderate Resolution Imaging Spectroradiometer (MODIS), on board the NASA satellites Terra and Aqua. AOD measures the concentration of aerosols or solid and liquid particles suspended in air that can arise from human activities, such as driving and construction, or natural factors like dust and water vapour.
His analysis shows the worst air quality in a 50km radius around Connaught Place and the cleanest in a range of 150-200km, showing how urbanization causes pollution.The AOD around Connaught Place ranged from 0.6 to 0.7, whereas in the US it was less than 0.2.
Kumar says industries and burning of garbage and plant matter could also be driving up air pollution, especially in winter when a blanket of cold air makes the dispersion of pollutants difficult. About ve hicles, he says, they are among the main sources of PM2.5 and reactive gases, such as nitrogen oxides and carbon monoxide, and volatile organic compounds. “If the city wants to cope with air pollution, it needs a multi-sectoral approach.“
Kumar is also tracking the impact of the odd-even experiment in Delhi but hasn't drawn any conclusions yet.“Weather plays an important role in dispersion and transport of air pollution. The 1952 London smog was caused by high levels of air pollution and cold air masses.“ But he says halving the number of diesel vehicles on the road will certainly reduce people's local exposure to pollutants.
Kumar is running a map: precise.ccs.miami.edudelhi that shows air pollution data in real-time. Each place, he says, has a more or less fixed capacity to disperse air pollution. “The capacity will remain the same in the future unless artificial filters are installed to check the increasing pollution in the city . The problem is that the pollution from anthropogenic (human) activities has been increasing dramatically without any effective mechanism to clean the air pollution, assuming it will disperse automatically .“
Causes of pollution
The share of various sources of pollution in Delhi in 2018
2000-18: growth in number of vehicles
Stubble burning in neighbouring states may be drawing everyone’s attention during the peak pollution days in the capital in pre-winter harvest season, but it is the vehicular emission which is the biggest culprit followed by industrial emission in making Delhi’s air dirty.
Both these sectors pollute the entire NCR the most round the year through emitting different kinds of pollutants while biomass burning simply adds to the woes during a short period of 15-20 days.
The ministry of earth sciences (MoES) on Monday released its new emission inventory, showing how transport and industry emit highest amount of pollutants whether it is the deadly PM2.5 or the hazardous nitrogen oxide (NOx) and sulphur dioxide (SO2).
“The emission inventory suggests that there is a substantial increase of emissions from transport and industrial sector (in the past eight years), while the contribution from residences have shown a substantial decline,” said the MoES secretary, M Rajeevan.
The emission inventory is the most effective tool used to identify and quantify the amount of pollutants emitted into the air. It may help the government in dealing with the problem through policy interventions by factoring in real reasons of pollution.
In its comparative analysis, the ministry’s report shows that the total emission of PM2.5 (particulate matter less than 2.5 micrometres in diameter) increased in the city by 15% in 2018 as compared to 2010. It also shows the transport sector emitted the most PM2.5 (41%) followed by wind blown dust from roads and other sources (21.5%) and industries (18.6%) in the capital. The PM2.5 can penetrate deeply into lung and cause respiratory problem.
Asked the status of emission from stubble burning, Rajeevan told TOI that the report did not take into account emission from crop residue burning as it is a seasonal phenomena which is restricted to only few days during the harvest period. “Overall, its contribution is not much if you look at the annual emission inventory data,” he said.
A comparative study shows that the emission from residential sector has been reduced drastically in 2018 as compared to 2010 due to high penetration of LPG connections. The ministry claims it to be the result of the government’s Ujjwala scheme which is meant for providing LPG connections to BPL families. It, however, says the burning of cow dung cake in outskirts of Delhi and brick kiln making are hampering the gain of LPG replacement to an extent.
Asked about emissions from transport and industrial sectors when everyone these days has been talking about stubble burning, Sunil Dahiya, clean air campaigner of the Greenpeace India, said, “Industries and transport are the most important consistent sources of pollution throughout the year and should not be allowed to hide behind biomass burning which must be tackled but is a 15-20 days episodic event.”
Referring to the launch of ‘Air Quality Early Warning System’, Dahiya aid, “We hope that the forecasting and prediction system will help take stringent actions on polluting industries and transportation system as well.”
2000-2017: Why Delhi’s pollution has been growing
DPS RK Puram Study Analysed Met Data From 2000 To 2017
The increase in Delhi’s pollution levels in the last few winters may be attributed to meteorological conditions, which are not only bringing pollutants from north India due to stubble burning, but also trapping it in the capital — a study by Delhi Public School (RK Puram) has found.
The study— which analysed IMD’s data between 2000 and 2017— found that there had been a slight increase in relative humidity, coupled with a drop in average wind speed over the past five years. It further spotted changes in wind direction over this period and found that there had been a shift in the direction from northwest in 2000 to north in winter months, which directly brought in stubble burning pollutants from Punjab and Haryana.
The study was carried out to determine the factors responsible for the increase in pollution during winters and looked at a number of parameters, including wind speed and directions, PM 2.5 and PM 10 levels, temperature variations, rainfall and humidity levels, the school said.
It found that in terms of wind direction, there had been a general change from northwest and north of northwest in 2000 to northern winds, which was first observed in 2010 and in particular in the past two years.
“This explains why high pollution is observed in October and November. Winds from Punjab and Haryana were bringing in particulate matter that persists in Delhi as it acts as a sink. Diwali and New Year celebrations with firecrackers further add to pollution levels,” the study stated. The research found two other factors that assisted this phenomenon — relative humidity and wind speed.
While between 2000 and 2017 there had been a general rise in wind speeds until 2010, thereafter a decline was reported. The average wind speeds in Delhi fell from 3m/s to less than 2m/s in the last five years — meaning there was less air movement and dispersal of pollutants.
The study also pointed out the increase in average relative humidity between 2000 and 2017 from 56% to over 61%, which provided more moisture in the air to trap the particulate matter.
“The IMD data from 2000 to 2017 was analysed for around two months to determine the reasons for the change in Delhi’s weather and why pollution levels have been rising. The study also looks at why occurrence of loo has reduced, which has been primarily attributed to an increase in morning and evening temperature variations,” said Niva Chhonkar, head of biology department, and one of the researchers.
The project was handed over by the principal, Vanita Sehgal, and chairman of DPSS, VK Shunglu with the other researchers, including the head of geography department Rupa Das and students Aryaman Sharma and Anandita Tewari of Class XI.
2000-2017: Delhi’s pollution has been growing because of increase in humidity, drop in wind speed and change in wind direction
2017-18: 26% in summer/ 36% winter is Delhi’s fault, rest external
Summer Share Is 26%, But Factors Outside India Damage More
Delhi itself may be responsible for just 26% of its PM2.5 (microscropic, respirable particles) pollution, a new study released on Thursday revealed. This figure goes up to 36% in the winter months. Most of the pollution in this category are attributed to upwind regions beyond the city.
These are the findings of the source-apportionment study jointly carried out by The Energy and Resources Institute (TERI) and Automotive Research Association of India (ARAI) to derive sectorial contributions to air pollution in Delhi and NCR. Data for the study was derived from 10 days of air quality monitoring in nine stations in Delhi, four in UP and seven in Haryana in winter and summer of 2016-17.
The study says Delhi itself contributes around 26% to the microscopic particles concentration in summers while NCR contributes around 24%. A whopping 33% come from “upwind regions outside India” and another 17% from “upwind regions outside NCR”. In winter, Delhi accounts for around 36% of the PM2.5 level, while NCR adds 34% and regions outside NCR and India together contribute 31% of the polluting particles.
“In summers, the contribution of outside sources is higher on account of higher wind speeds and enhanced atmospheric transport of pollutants,” explained the study. “In the NCR towns, the contribution of emissions from Delhi varied as per their location with respect to Delhi and prevailing winds with Noida, which is downwind of Delhi, receiving 28% and 40% of its PM 2.5 concentrations from Delhibased sources, respectively, in summer and winter.”
The study made use of two approaches to calculate the sources of pollution in the region: a receptor model involving chemical analyses of all samples collected from the 20 stations, and a dispersion model aimed at capturing the dispersal and movement of pollutants from the sources to the monitoring stations. In both the models, Delhi’s leading source of pollution in summers was ‘dust’, which contributed to around 38% of the total PM2.5 concentration. In winters, industry and transport were the major contributors, injecting 30% and 28%, respectively, in the PM2.5 levels.
The report noted that within the 30% contribution of industries, brick-making accounted for 8%, power stations 6% and stone crushers 2%. In transport’s 28% share, trucks were responsible for 8%, twowheelers 7%, three-wheelers 5% and cars a mere 3.4%.
“It is shocking how low Delhi’s contribution to the pollution is,” said Ajay Mathur, director general, TERI. “It shows that action is required not just in Delhi, but in the entire NCR region and even beyond, particularly areas upwind of NCR.”
The study suggests remedial measures such as enhanced LPG penetration to reduce biomass burning, use of agriculture residue in power plants to prevent crop burning and coal usage, and stringent pollution standards for industries, among others.
“If the present measures remain and additional measures suggested are implemented, there can be considerable drop in PM2.5 and PM10 levels by 2025-2030,” said Mathur. The study had taken as factors the secondary pollutants created due to sulphur oxide and nitrogen dioxide emissions never before included in pollution studies.
Crop stubble fires
Account for 70% of pollution on some days
Crop fires sometimes have 70% share in Delhi’s air pollution Amit Bhattacharya, `Crop fires had 70% share in city's peak air pollution' Contribution, Nov 08 2016 : The Times of India
Up From Zero On Nov 1: Expert
Crop fires in Punjab and Haryana contributed as much as 70% of the pollution load in Delhi on Sunday , [6 Nov] the city's worst air day in a long time, a leading government scientist said, basing his assessment on computer models used to determine the capital's air quality index.
Gufran Beig, program di rector of Safar (System of Air Quality and Weather Forecasting and Research), under the earth sciences ministry, said on Monday that the proportion of pollutants from crop fires in Delhi's air rose dramatically from almost zero on November 1 to a peak of 70% on November 6.
“Safar's chemistry transport model gives a clear picture of the share of pollution from external sources. It shows pollution load from crop fires in Punjab and Haryana rose steadily after November 1 due to favourable upper air winds,“ Beig said.
The smog cleared significantly on Monday , helped by a pick-up in surface winds and a change in upper-air direction. “The share of cropburning in Delhi's air quality was down to 50% and dropping,“ the scientist said. Like a perfect storm, various factors fell in place to create the dense smog spell over NCR, which SAFAR programme director Gufran Beig described as an “extreme pollution event“.“While the surface air was calm over the capital, upper air wind direction changed around November 1, when winds blew in from between west and north, directly transporting pollutants from crop fires,“ the scientist said.
The calm surface winds and an air ridge over NCR prevented the pollutants from dispersing, leading to an accumulation of toxic chemicals in the air.
Beig said the PM 2.5 concentrations in Delhi's air were at unprecedented levels on Sunday .
“Since we started SAFAR five years ago, we have never seen the value of PM 2.5 concentrations crossing 700µg m3. Just as extreme weather events are increasing so are extreme pollution events such as this one,“ he said.
SAFAR's figures on contribution of biomass burning in Delhi's air pollution come on a day when Union environment minister Anil Madhav Dave said crop burn ing was responsible for just 20% of the pollution level in the national capital.
That figure is based on source apportionment studies that have variously put the external contribution to winter pollution in Delhi at 20% to 35%. Beig said these studies give an average which would hold true in general terms but can't be used for specific events.
“This is like telling you what the normal rainfall at a place is. SAFAR's figures, on the other hand, are based on the actual conditions that existed during this period,“ the expert said.
Due to surface winds picking up, Beig predicted that the pollution levels would drop on Tuesday , while still staying in “severe“ zone, and come down further to “very poor“ levels on Wednesday .
The Times of India, December 20, 2016
Jayashree Nandi Industry's top choice of fuel cheap but deadly
EPCA's Plea In SC To Ban Use Of Furnace Oil Brings Threat To Air In Focus
The national capital region (NCR) may be one of the most polluted regions in the country but many industries located are still running on an extremely polluting fuel -furnace oil.
A substantially cheaper alternative to natural gas and diesel, FO, as it is called in industrial terminology , is marginally better than bitumen in quality .It emits substantially higher particulate matter (PM) and secondary sulphate particles, said scientists.
The widespread use of FO came to light only recently after the Supreme Court-mandated Environment Pollution Control Authority (EPCA) investigated its use in NCR and submitted a report to SC. The report also highlighted the use of pet coke, another high sulphur fuel, in NCR.
Industries in Ghaziabad's Sahibabad and Loni Road industrial areas admit that they use FO despite knowing how harmful it is for environment.A large steel company TOI visited in Sahibabad, for instance, runs its generator on FO and natural gas.
“It's a 30:70 ratio, with FO making 70% of the fuel. It's cheap and serves the purpose. I don't think the Supreme Court can ban it because industries are a powerful lobby . Also, what will oil refineries do with the FO they generate?“ said its head of purchase. FO is priced around Rs 25 per litre, compared to Rs 56.76 for diesel, Rs 69.3 for petrol and Rs 24.5 per standard cubic meter for piped natural gas.
About three months ago, the price of FO fell to Rs 15 per litre due to the dip in crude oil prices. “The prices fell seven times in the past year or so. It just makes economic sense for industries to opt for a cheaper fuel. Of course, it's way more polluting and you can tell from the chimney smoke whether a factory is using FO. It's usually black or blue smoke. That's why we invested in piped gas supply ,“ said a senior representative from another steel company's hot rolling and heat treatment division.
TOI also found several dyeing, paper recycling and glass industries using FO.
A representative from Indo Petro, a dealer, said, “Many industries in Delhi too use it illegally because it's cheaper.“
Anant Bhargav, director of IFP Petro Products, said, “The government can have Bharat Standard (BS)-type norms for industrial fuel. Some industries even use very toxic tyre oil made from used rubber and ty res. Major dealers supply these fuels.“
Around 30 forging industries use FO in Ghaziabad, added an Industrial Area Manufacturer's Association member.
Mukesh Sharma, scientist at IIT Kanpur and author of Comprehensive Study on Air Pollution and Green House Gases (GHGs) in Delhi -the latest source apportionment study , said, “The PM emissions from FO are substantially higher than other liquid or gaseous fuels. Since the sulphur content in FO and pet coke is high, a large amount of sulphur dioxide (SO2) is released that converts into fine sulphate particles in the atmosphere.“
The sulphur content in FO is 15,000 to 20,000 ppm and about 70,000 ppm in pet coke compared to around 50 ppm in diesel. Scientists recommend that high sulphur fuel should only be used in cement industries because the calcium oxides generated in these factories can neutralise the sulphur emission.
During a recent hearing in SC, a lawyer representing the Centre sought time to respond to EPCA 's submission. The apex court has given the Centre four weeks to examine whether pet coke and FO, if used as industrial fuel, is harmful.
“In case the government comes to the conclusion that its use is indeed harmful, it may consider issuing appropriate directions in terms of Section 3(2)(v) of the Air Act,“ the order said.
According to EPCA 's report, a big manufacturer of solar panels, a glass company and steel companies are using FO. Apart from PSUs, a private company also supplies FO.
Factories in residential areas
Polluting Units Flourish In Residential Areas Of City
Many residential areas in Delhi are no longer distinguishable from planned industrial areas. This is because thousands of polluting industries brazenly run from these places right under the nose of the authorities. The Delhi State Industrial and Infrastructure Development Corporation (DSIIDC) listed 51,837 units operating from non-conforming/residential areas and asked the three municipal corporations to initiate action against them.
Delhi’s air, already polluted by dust, industrial and vehicular emissions and soot from crop burning, is additionally assailed by these illegal industrial units that deal with dyes, chemicals, rubber, asbestos, plastics, electrical and auto spare parts, iron smelting and fluorescent lights.
These pollute water by discharging effluent directly into drains and air by emitting noxious particles. In 1996, DSIIDC had, under the relocation scheme for industrial establishments, allotted plots to factory owners running their units from residential areas. And as far back as 2003, the Supreme Court, in its judgment in MC Mehta v Union of India, had directed that all industrial units that had come up in non-conforming areas on or after August 1, 1990 should be closed within a given timeframe. But, even in 2018, as the DSIIDC listing proves, they continue operations from residential areas.
According to Master Plan Delhi 2021, only 28 domestic small-scale industries like matchstick making, incense sticks and garland making are allowed from residential areas. Under MPD, all polluting industries are to be shifted out of Delhi by 2021.
The analysis of the data released by DSIIDC shows most violations in Moti Nagar, Kirti Nagar, Ramesh Nagar, Jangpura, Najafgarh and Mansarovar Garden, all in west Delhi, Bhogal, Ashram, Mahipalpur, Maharani Bagh and Jangpura in south Delhi, Gandhi Nagar, Jheel, Shastri Nagar, Kailash Nagar, Jafrabad and Shahdara in east Delhi; and Sadar Bazaar, Chandni Chowk, Malkaganj, Ballimaran, Lal Kuan and Kashmere Gate in north Delhi. Other highly affected areas are Karol Bagh, Patel Nagar, Anand Parbat, Rohtak Road, Rajinder Nagar, Old Rajinder Nagar in central Delhi, Shahdara, GT Road, Babarpur and Vishwas Nagar in northeast Delhi, and Burari and Jagatpuri in northwest Delhi.
In 2014, NGO Toxics Link identified 18 hotspots in Delhi, including Samaypur, Badli, Okhla, Ghazipur, Mayapuri, Moti Nagar, Yamuna Vihar, Gokulpuri, Shastri Park and Wazirpur. The report cited Central Pollution Control Board’s data for 2010 showing Delhi among the cities with the most polluted air. “In 1975, vehicular population in Delhi and Mumbai was same. But by 1997, Delhi had three times more vehicles than Mumbai. Vehicular pollution contributed 6% of the total air pollution load in Delhi. Another 25% was generated by industries and coal-based thermal power plants,” the report stated.
The municipal corporations have only listed 32,541 illegal factories in areas under their jurisdiction — 11,805 under the East Delhi Municipal Corporation, 11,214 under the north body, and 10,023 in the south. EDMC has so far verified 2,251 units, and reported that 1,145 of these were found to have shut down. “The survey is going on, and we have issued notices to the industries that we have inspected so far,” said an EDMC official. The north civic body, in its survey, found 9,522 units operating from residential areas, while 874 it had listed were found vacant and 818 were sealed.
Many of the listed units are either locked or closed, said SDMC officials. “We have directed the zonal officials to find out whether the industries deemed to be operating illegally were still running or had shut down. Those still found operating will be sealed for failure to relocate as required by the Delhi Municipal Corporation Act,” said an SDMC official.
Sources in the civic bodies disclosed that these industries are illegal not only because they run from unauthorised areas, but also because they do not have the licence to operate. “It is totally up to the enforcement agencies to keep track of the polluting factories operating from residential areas,” a source declared. Despite several orders of Delhi HC and DSIIDC, the corporations have failed to take action. On July 9, hearing the Bawana Factory Welfare Association vs Govt of NCT & Others case, an HC bench expressed unhappiness “on the tardy action on this issue by the corporations”.
Dust in Delhi
131 tonnes of dust are generated every day in Delhi
Dust pollutes Delhi more than cars: Government
Dhananjay Mahapatra & Amit Anand Choudhary
The Times of India Jan 08 2015
Concentration of particulate matter, SO2 and NO2 respectively by vehicles and industries
Dust is a major components of pollutants in Delhi
The various pollutants that contribute to Delhi’s air pollution, and their relative share
SC told vehicles contribute just 6.6% and dust's share is 52% : Ministry of Environment and Forest
The major source of pollution in the capital is dust particles and not vehicular emissions, the ministry of environment and forest (MoEF) submitted before Supreme Court. While dust contributed 52% of particulate matter in the air, pollutions from vehicles, including trucks and light commercial vehicles, accounted for just 6.6%, the ministry said.
“In Delhi, vehicles contribute only 6.6% particulate matter (PM) emission, 18.3% oxides of nitrogen (NOx) and 0.3% of noxious sulphur dioxide (SO2) emissions whereas dust particles from pavedunpaved roads contributed 52% of particulate matter pollution,“ the ministry said, quoting a Source Apportionment Studies conducted in Delhi, Kanpur, Pune, Mumbai, Chennai and Bengaluru.
“The source apportionment study carried out in Delhi reveals that re-suspension of the dust is also the major source of particulates in the ambient air. There is a need to focus on initiation of steps to reduce re-suspension of dust and managementregulation of construction activities,“ MoEF said.
Of the total particulate matter and NOx pollution caused by vehicles, private cars were responsible for 22% while trucks caused 45.8% and light commercial vehicles 27%, it said.
“Industry power plants contribute 78% of NOx and 95.4% of SO2 content in the ambient air,“ the ministry said. It also responded to several suggestions made by se nior advocate Harish Salve, who as amicus curiae had personally filed an application drawing the court's attention to the deteriorating ambient air quality of the capital, which squandered the advantage of converting its entire city passenger transport fleet to cleaner fuel CNG on court's orders more than a decade back.
Clarifying that the National Green Tribunal headed by former SC judge, Swatanter Kumar, was already seized of the issues raised by Salve, the ministry said Salve's suggestion to restrict plying of private cars on alternative days might not be feasible.
“It may not be an effective and feasible option as people using personal cars are not likely to shift the mode of travel. Persons using two-wheelers are likely to shift to public transport, which may lead to excessive pressure on services without yielding much benefit,“ it said and informed the court that it has sought views of public transport providers on this issue.
Salve had also said schoolchildren were the worst sufferers of the deterioration in ambient air quality and suggested closure of schools on `red alert days', when the air quality nosedives. “Exposure of school going children to higher level of pollution occurs only for limited period during travel, while Air Quality Index (AQI) is based on 24hourly average standard and prolonged exposures. Moreover, most schools are closed for winter breaks (when the air quality becomes worse),“ it said.
The ministry of road transport and highways said that “it is high time that the pollution control authorities conduct studies for apportionment of causes of pollution in habitations including Delhi.All increase of pollution is always ascribed to automobiles based on studies done overseas“.
Green activists disagree
The Times of India, Jan 09 2015
Green activists: Govt misled court on Delhi's pollution
The government's submission before the Supreme Court that the major source of pollution in the capital was dust particles, and not vehicular emissions, was dismissed by environmental activists as ridiculous, with some even questioning the intent behind the environment ministry's stand.
The ministry of environment and forest had told the court that dust was responsible for 52.2% of the pollution load in Delhi while vehicles contributed only 6.6%. But a paper by the Indian Institute of Tropical Meteorology , which started maintaining Delhi's air quality data since the Commonwealth Games, says vehicles contributed to 32% of the total particulate matter of size 2.5 micron and less (PM 2.5) in 2010. The figure has since risen to 36%. Other sources, including unpaved roads and construction activity, contributed 28% in 2010, which came down to 26% in 2013. Sources pointed out that the MoEF report talks about PM in general, not drawing a difference between PM 10 and PM 2.5. The latter is universally considered to be the more harmful of the two, and its levels are considered when drawing up policy.
Questioning the intent behind MoEF's submission, the Centre for Science and Environment accused the ministry of trying to scuttle the role of vehicles in Delhi's rising air pollution “at the behest of automobile companies as combating pollution today requires tough measures to restrain cars and encourage public transport“.
The IITM report, titled `Emissions inventory of anthropogenic PM2.5 and PM10 in Delhi during Commonwealth Games 2010' and authored by Saroj Kumar Sahu, Gufran Beig and Neha S Parkhi says, “The present estimated wind blown dust is more than the total estimation from all other sources and more than four folds in comparison to transport emission. The resuspended dust is associated with the vehicular movement on the road and is directly proportional to the number of ve hicle, its weight and speed as well as the amount of dust on roads.“ It also states that vehicles are the likely cause for even this. “It is likely to be more serious in a city like Delhi due to more vehicles...H ence the transport sector which has direct contribution through fossil fuel combustion and indirect related to road condition provide the key to better air quality in NCRD if properly mitigated.“
Anumita Roychowdhury , who heads CSE's clean air campaign, said, “MoEF has only cited the PM10 inventory , which is the coarse particles.Their limited study , which looked at PM 2.5 levels, was withdrawn by NEERI as it was based on a flawed methodology and ended up blaming cooking LPG for 61% of PM2.5 in Delhi.
Even after stating the government has implemented the SC order on relocation of polluting industries, the re port claims that industry and power plants are still responsible for 78% of nitrogen oxides and 95.4% of sulphur dioxide in the capital. Point is, even dust becomes the carrier for emissions.“
A study carried out by CSE has found that on national holidays when traffic volume is less, pollution is lower.“For instance, on Republic day of 2013, PM2.5 levels in RK Puram declined compared to the previous day from 244 microgramme per cum to 153 microgramme per cum and again rose to 178 microgramme per cum on January 27 and to 345 microgramme per cum by January 28. Similar trends were observed elsewhere,“ said Roychowdhury .
40% smog was Gulf dust; Stubble Burning 25%/ Nov 2017
Stubble Burning Contributed 25%; Rest Local Emissions
Dust travelling thousands of kilometres from a severe storm in the Gulf contributed significantly to the weeklong killer smog that choked Delhi-NCR and much of north India from November 7 onwards, an analysis by the government’s air quality research body, SAFAR, has concluded.
SAFAR said dust coming in from the Gulf constituted nearly 40% of pollutants in the smog while stubble-burning in Punjab and Haryana contributed around 25%. Making up the remaining 35% was pollution produced locally in Delhi-NCR.
In a nightmarish confluence of factors, favourable upper winds carried the dust from the Gulf and smoke from crop burning into Delhi-NCR while an anti-cyclonic wind circulation over the region pushed these pollutants towards the surface and trapped them there as surface conditions were calm.
The incursion of these pollutants began on the night of November 6 and continued till November 10, said Gufran Beig who heads SAFAR. “By 5pm on November 7, the air quality had dropped to severe levels,” he said.
PM 2.5 concentration was recorded at 537 micrograms (µg)/m3 on November 7, nine times the 24-hour average standard. It rose to a peak of 640 g/m3 the next day. According to the SAFAR analysis, if external sources of pollution had not played a role, Delhi’s air quality on November 8 would have been closer to 200 g/m3.
More significantly, the analysis said that the measures initiated by the environment pollution control authority (EPCA) under the graded response action plan (GRAP) may have helped reduce pollution by as much as 15%. That was the observed offset in SAFAR’s offline model between known anthropogenic and weather induced natural sources and observations from the ground.
The incursion had ceased by November 10, SAFAR said. “There was no pumping and influence of stubble burning and Gulf storm dust after November 10 night, owing to slowing down of upper air winds and change in wind direction,” the analysis stated.
The storm had hit Saudi Arabia, Iraq and neighbouring countries on October 29, sending a massive cloud of sand and dust into the air that was visible in NASA satellite images. SAFAR said the storm continued up to November 4. This dust rose 1.5 to 3km into the atmosphere “where winds became very strong (15-20kmph) and direction became towards India (westerly, north-westerly) and dust affected larger region of Delhi.”
While local weather conditions had taken over by November 11 evening, it took another couple of days for pollutants to get flushed out of the region, it said. This was because the inversion layer (the height at which a warmer layer of air exists) fell from 1,600m to just 45m in eight hours on November 11, trapping pollutants close to the ground and delaying recovery of air quality by another two days.
Non-linear city structure; poor air circulation
A professor of environmental studies at Jamia Millia Islamia has claimed that the studies conducted on Delhi’s air pollution are faulty as these were conducted against wrong parameters.
Citing the non-linear and amorphous structure of the city and poor air circulation as the major reasons behind the city’s air pollution, S M Akhtar suggested creation of microforests perpendicular to major wind directions in the city and making winter a no-construction season.
The studies on air pollution in Delhi have failed as these have used the same tools as those applied in linear cities like Mumbai, Kolkata and Chennai, Akhtar said. “There is a need to study Delhi’s urban form and population density pattern.” Delhi is a city that is expanding at all directions, he added.
Akhtar claimed that the major source of the environmental problem is yet to be identified. “I believe that the major source of pollution is dust particles from construction sites and material transportation that also catalyse depletion of watersheds and green mass of the city.”
Accordingto his study, Delhi’s concentric form and growth makes the replacement and natural revitalisation of air mass polluted by human activities very tough. “This was corroborated when we witnessed the comparison of the linear north-south urban forms of Mumbai, Chennai and Kolkata though they have a higher population density.”
Elaborating the point, Akhtar said that in linear cities, the form and orientation allows the east-west wind that travel in India to regularly replace the air mass in the city. “The linear form also allows a spinal public route for transportation that is difficult in a circular city like Delhi as it has multiple and longer routes that makes it a compulsion for many to increasingly use private transport, leading to congestion.”
The professor suggested improvement of public transport as a major step to help Delhi. Akhtar also said creation of micro-forests perpendicular to the major wind directions of the city would replenish air “much like how it was done in New Raipur”.
New green patches will also improve the city’s rainwater retention capacity and replenish groundwater, he added.
One of the disastrous impact of unceasing rise in population and prosperity has been a rise in air pollution. Level of air pollution in Delhi, 2001-17
Relaxes Ban On Construction, Entry Of Trucks
The Supreme Court-appointed Environment Pollution Control and Prevention Authority (EPCA) on Monday asked a task force led by the Central Pollution Control Board (CPCB) to consider banning all vehicles, except those running on CNG, in the capital during bad air days, keeping in mind the high pollution levels post-Diwali in the city.
The EPCA urged the task force to “consider” this measure and to recommend if it needed to be brought into the National Capital region (NCR) soon, if the next few days see continuation or deterioration of the air quality.
“We will, based on this discussion and review of the air quality situation, inform you tomorrow of this or other measures that would need to be taken to contain pollution in the region,” EPCA chairperson Bhure Lal said in a letter to NCR authorities.
“Public health is of utmost priority and this emergency step may be the only option we have,” the letter, a copy of which is with TOI, states.
Earlier in the day, the task force relaxed the ban on construction activities in NCR and also partially allowed trucks entry into Delhi. “In view of poor dispersion, low temperatures and high humidity during night hours, construction activities and truck traffic (into Delhi) may be permitted only during daytime between 6am to 6pm… Enforcement agencies should keep strict vigil and ensure firm actions against the violators,” it said.
The ban on industries using coal and biomass, including brick kilns, will be lifted on Tuesday. This ban did not include power plants and waste-to-energy plants.
Diesel use and air pollution on a rise in Delhi
Air pollution and Diesel use rising fast in Delhi
December 17, 2014
Consumption of diesel in Delhi has been increasing steadily since 2010 while that of petrol is declining. Simultaneously, air pollution--especially the concentrations of PM 2.5 (fine, respirable particles) and PM 10 (coarse pollution particles) --is on the rise.
Diesel consumption peaked in Delhi in 2007-08 at 13.94 lakh metric tonnes but then declined to 8 lakh tonnes in 2010, possibly due to higher taxes on the fuel. But it has been rising sharply again since 2011. In 2012-13 it stood at 10.29 lakh tonnes and reached 11.29 lakh tonnes in 201314, a 10% increase.
Particulate matter (PM) is associated with diesel emissions. Analysis by Centre for Science and Environment (CSE) shows PM10 levels have increased by about 75% since 2005 with occasional dips.
Anumita Roy Chowdhury of CSE's Clean Air Programme says increasing diesel consumption in Delhi is worrying. “The data only shows massive dieselization in Delhi. Diesel primarily contributes to emissions of particulate matter (PM) and oxides of nitrogen (NOX), which are both increasing.“
She said diesel vehicles emit five times more PM than petrol vehicles. “I think die sel and, if required, diesel vehicles need to be taxed in a way that the increased revenue can be used for refineries to produce clean diesel.Delhi needs 10ppm sulphur fuel by 2020,“ Roy Chowdhury added.
Diesel pricing was de-regulated earlier this year, which means it is now linked to the global market without any government intervention.
The other concern with diesel consumption is its health consequences. World Health Organization has graded diesel emissions as carcinogenic (causing cancer). Roy Chowdhury said that it is in the same category as tobacco.
The consumption of CNG has increased from 5 lakh metric tonnes in 2009 to 6.98 lakh metric tones in 2013-14.Consumption of kerosene has seen a sharp decline over the years from 1.62 lakh metric tonnes in 2006 to 1.07 lakh metric tonnes in 2010 and just 9,000 metric tonnes in 2013-14.
Stubble burning adds to Delhi's pollution: Nasa
A new study by Nasa scientists has concluded that there is a strong link between agricultural fires in Punjab and Haryana and PM2.5 levels in Delhi during the post-monsoon months of October and November.
PM2.5 concentrations in Delhi, which is downwind to Punjab and Haryana, show a coherent increase — rising often from as low as 50 micrograms per cubic metres (µg/ m3) before the onset of the burning season to 300µg/m3 at the beginning of November when burning is under way.
During the crop burning season of 2016, the seven-day average peaked to a record high of 550µg/m3. This could also explain the severe smog episode in November 2016 when PM2.5 concentration peaked to more than 700µg/ m3 on November 5, 2016. But the study also cautions that the impact of emissions from local sources, including more than 9.5 million vehicles, industries and construction activities, cannot be ruled out. However, this study could give the government clues to averting smog episodes. While the link between crop burning and winter pollution peak was being speculated for long, this is the first scientific study to correlate fire counts in Punjab and Haryana with wind direction and parallel rise in PM2.5 concentrations in Delhi.
The study that analysed satellite data for 15 years (2002-2016) also revealed an increasing trend in crop fires. It found that there is a shift in the distribution of fires from October to November. This study, which has been accepted recently to be published in the journal of Aerosols and Air Quality Research (AAQR), uses fire data from satellites, pollution data from Nasa’s A-train sensors and PM2.5 concentrations measured at the US Embassy in Chanakyapuri.
Scientists also conducted aback trajectory (path taken by air pollution particles in the past) using a National Oceanic and Atmospheric Administration (NOAA) model. Compared to paddy stubble burning in October-November, fire counts in May (wheat stubble burning season) were found to by lower by a factor of six to eight.
As far as post-monsoon pollution is concerned, just by excluding PM2.5 data for October and November, the annual mean concentrations decreased by 10%, 7%, 12% and 13% for 2013, 2014, 2015 and 2016, respectively. “Overall, the fire counts and PM2.5 concentrations showed a linear relationship, which yields an increase in PM2.5 of 33µg/m3, given an increment in fire counts by about 100 …” the study concluded.
Back-trajectory modelling also gave scientists a clue as to why Delhi may be worst affected by crop fires. Days with extreme levels of PM2.5 were mostly associated with northwesterly winds from crop burning areas, “suggesting a profound impact of smoke transport on modulating air quality over Delhi”, the study said.
While concluding that crop fires are on the rise in Punjab and Haryana, satellite data also reveal that the number of fires was higher in October between 2002 and 2009. But this trend has now changed and a majority of fires are being recorded in November.
The number of fire counts detected between 2009 and 2016 was found to be 32% higher than those found between 2002 and 2009 by one of the satellites. But, in 2016, fires were at a record high, which also possibly explains the severe smog episode in 2016 in Delhi. “The crop burning season of 2016 has been most anomalous with maximum fire hotspots (17,804) detected over the Punjab-Haryana region … compared to average fire counts (14,310) detected between 2011 and 2015, the total fire counts in 2016 were 24% higher,” the study added.
In 2016, fire counts were up by 44% compared to the average count recorded between 2002 and 2015.
The study was led by Hiren jethva, scientist from the Universities Space Research Association at the Nasa Godard Space Flight Center; co-authors include scientists Duli Chand, Omar Torres, Pawan Gupta, Alexei Lyapustin and Falguni Patadia. The Pacific Northwest National Laboratory and Morgan State University were also part of the study.
Vehicles from neighbouring areas add to Delhi pollution: CSE, 2016
The Times of India, June 4, 2016
Delhi has the distinction of having the highest vehicular population among the metros. However, the actual daily number of the roads is much higher than the figure of 88 lakh that is toted out as the number of cars in the capital.This is because there is a massive daily influx of passenger and commercial vehicles from other parts of the National Capital Region.
In fact, a new Centre for Science and Environment (CSE) survey has found that the number of vehicles entering Delhi daily is almost as many as those that are registered in the city every year. The video recorded survey showed an average of 3.7 lakh cars and 1.27 two-wheelers entering the city every day . If all 124 entry points to the capital were considered, the number could be as high as 5.65 lakh. CSE recalled that the Economic Survey of Delhi for 2014-15 had found 5.69 lakh vehicles were registe red in Delhi that year, of which cars and SUVs accounted for 1.65 lakh vehicles.
The study was conducted in June 2015 through 24-hour video recording of all categories of vehicles entering and exiting Delhi at nine entry points. These included Kundli border on NH1; Tikri border on NH10; Rajokri on NH8; Badarpur on NH2; Kalindi Kunj; two points at Ghazipur border on NH24; and two points at Shahdara border on NH-19.
The survey , released to mark the World Environment Day on June 5, said that the effort to reduce the number of trucks entering the city by imposing an environmental compensation charge seemed to have been negated by the large number of passenger vehicles coming to Delhi.
“Delhi's battle against pollution, congestion and energy guzzling can get more difficult if its own explosive motorisation gets further aggravated by the huge daily influx of vehicles from outside,“ said Anu mita Roychowdhury , executive director, CSE. “This new analysis reconfirms that ineffective public policy on public transport connectivity is increasing dependence on personal vehicles, leading to enormous pollution and ill-health in Delhi-NCR.“
She also pointed out that an equal number of vehicles went out of Delhi daily, contributing to pollution in the NCR towns as well.
Researchers found that of the approximately four lakh cars entering the city , 55% were cars, 11% SUVs and 27% were two-wheelers. The number of two-wheeler entering the city -around 1.65 lakh from all entry points -is 43% of all new two-wheelers registered in 2014-15.
CSE highlighted the fact that cars driving into Delhi had the highest per capita CO2 emissions at nearly 3,031 gramskm, followed by SUVs at 1,919 gmkm. The buses crossing the border had the smallest CO2 footprint at 539 gm km. “ Against this trend, how will Delhi-NCR participate in India's commitment of an intended national determined contribution of reducing energy intensity by 35% by 2030?“ wondered the green body .
The survey also found that the total number of diesel cars, taxis and SUVs entering Delhi are 2.5 times the total registration of diesel vehicles in the city in 2014-15. “Among all the fuels used in Delhi, diesel still remains the highest. To that is added the daily influx of diesel vehicles that are higher than the local fleet,“ CSE said in its statement.
Now wonder, the organisation said, lung cancer incidence in the city has increased by over 33.3 % since the middle of the last decade. It warned that growing motorisation and dieselisation were continuously adding to the toxic risk in Delhi where the National Cancer Registry Programme showed the highest increase in lung cancer risk among all metro cities.
Effects on health
2013-17: 17 lakh respiratory infections, 981 deaths
Parl Report Highlights How Polluted Air Is Huge Risk Factor
The capital witnessed 981 deaths due to Acute Respiratory Infection (ARI) from 2013 to 2017. Over 17 lakh others were diagnosed with ARI, stated a standing committee report tabled in Parliament on Tuesday.
The report said the polluted air in Delhi-NCR is a significant risk factor for a number of pollution-related diseases and health conditions, including respiratory infections, and recommended immediate corrective and preventive strategic steps in consultation to mitigate the air pollution.
The committee, which held three meetings with authorities concerned and analysed the whole gamut of air pollution in Delhi-NCR in the past nine months, said it was surprised to note that the health ministry was not taken on board in the high-level task force on air pollution which is, in a way, indicative of ignorance as well as denial about negative impact of air pollution on human health. “The committee recommends that considering the severe health hazards of air pollution, ministry of environment, forest and climate change should take immediate corrective and preventive strategic steps in consultation with the health ministry,” the committee advised.
It has asked the health ministry to aggressively start an awareness campaign to educate people about the adverse health effects of air pollution, and the ways and means to minimise its adverse impacts.
In 2016, the World Health Organisation (WHO) put Delhi amongst the 20 most polluted cities in the world in terms of PM2.5 levels.
An epidemiological study conducted in 2008 on effects of air pollution on human health (adults) in Delhi, referred to by the parliamentary committee in its report, shows citizens of the city were more susceptible to respiratory symptoms compared with those living in rural areas.
The United Nations Children’s Fund (UNICEF) had said last year there is growing body of scientific research that shows that air pollution can permanently damage a child’s brain.
UNICEF also said that south Asia has the largest proportion of babies living in areas where air pollution is at least six times higher than international limits (10 micrograms per cubic metre). “Pollution is one of the biggest health hazards of our times. Apart from the government agencies, people need to realise this urgently too and take preventive measures,” Dr Arvind Kumar, centre for chest surgery at SGRH, said.
In a recent analysis conducted by him that involved 150 in-house patients suffering from lung cancer from March 2012 to June 2018, Dr Kumar found nearly half of the patients were non-smokers. While conventional wisdom states that smoking is its main cause, but now, there is strong evidence that points to the increasing role of air pollution in the rise of the cases, he said.
Calling polluted air in Delhi a significant risk factor for a number of pollution-related diseases and health conditions, the parliamentary committee on Tuesday said infants, children and asthmatic patients were most vulnerable to it.
Extent of pollution
Understanding air pollution in Delhi in 5 steps
See graphic, Understanding air pollution in Delhi in 5 steps
PM levels, 2009-17
See graphic, PM10 and PM2.5 levels, 2009-17
PM2.5, PM10 trends show failure to control local emissions
See graphic:, 2009-17, PM emissions decrease in Beijing but increase in Delhi
November’s air quality, 2016, 2017
See graphic, Air quality, November 2016-2017
2014: Ambient Air Pollution (AAP) database
Delhi has the worst air pollution in the world: WHO PTI | May 7, 2014
NEW DELHI: Delhi is the most polluted city in the world when it comes to air quality, according to a WHO study released today.
The 2014 version of the Ambient Air Pollution (AAP) database contains results of outdoor air pollution monitoring from almost 1600 cities in 91 countries.
India's national capital has the highest concentration of PM2.5 — particulate matters less than 2.5 microns— form of air pollution, which is considered most serious.
This form of concentration consists of tiny particles that put people at additional risk of respiratory diseases and other health problems, the World Health Organization said.
The situation is so bad in Delhi that its air has PM2.5 concentrations of 153 micrograms and PM10 concentrations of 286 micrograms — much more than the permissible limits.
In comparison, Beijing, which was once considered one of the most polluted cities, has PM2.5 concentration of 56 micrograms and PM10 concentration of 121 micro grammes.
Air quality is represented by annual mean concentration of fine particulate matter (PM10 and PM2.5, particles smaller than 10 or 2.5 microns).
The database covers the period from 2008 to 2013, with the majority of values for the years 2011 and 2012.
"Many factors contribute to this increase, including reliance on fossil fuels such as coal fired power plants, dependence on private transport motor vehicles, inefficient use of energy in buildings, and the use of biomass for cooking and heating," WHO said.
High levels of oxides of nitrogen (Nox) and particulate matter (PM)
The Times of India, Sep 1, 2011
Air pollution back as big health threat in city
Air pollution has again become a major threat to public health in Delhi, say environmentalists. With 69 lakh vehicles plying on city roads, a growth of about 60 lakh in 20 years, experts say oxides of nitrogen (NOx) and particulate matter (PM) are now at critically high levels.
NOx and PM are known to cause cancer and asthma. Medical experts say signs of deteriorating health are already manifest. The Delhi cancer registry maintained by AIIMS shows a 2-3% rise in lung cancer cases every year.
Dr Vinod Raina, a cancer specialist at AIIMS says till some years ago, 14-15 lung cancer cases were reported for every 1 lakh cancer patients. “Of late, we have been getting about 13,000 new cases of cancer each year, of which 10% come in with lung cancer. And, 30% of lung cancer patients have nothing to do with smoking,” he said.
The Centre for Science and Environment says vehicular pollution has returned as a big threat in Delhi. “About 55% of Delhiites stay within a 500m distance from main roads where vehicular pollution is at an all-time high. After public transport was converted to CNG, pollution has become invisible but is still on the rise,” said Anumita Roychowdhury, associate director, CSE.
“In the 1990s, when the issue of air pollution was first raised, only particulate matter was being monitored. Now there is also a red alert on NOx and PM. AIIMS has been tracking hospital admissions and has found that they have been rising in winter months when pollution levels rise,” Roychowdhury said.
BREATH OF FOUL AIR
Delhi cancer registry at AIIMS shows 2-3% rise in lung cancer cases every year. 30% of these patients don’t smoke 55% of Delhiites stay within 500m from main roads, where vehicular pollution is at all-time high Commuters travelling in AC vehicles suffer 35-55% less pollution as compared to those in autos Environmentalists say levels of NOx and particulate matter in Delhi’s air now a major threat to public health.
AC cars may keep you fit
Air pollution is posing serious health hazards for the people of the national capital.
Researchers from Berkeley University carried out a survey in Delhi between February and May 2010 to analyse the impact of pollution on those using public transport.
The study – Concentration of fine, ultrafine and black carbon particles in autorickshaws in New Delhi, India – published in Atmospheric Environment, says those travelling in autos and cars with windows rolled down are exposed to 1.5 times more PM 2.5 concentrations than the ambient air. Exposure to ultrafine particles are 8.5 times higher. Joshua Apte, who headed the research, said those travelling in air-conditioned vehicles suffered 35-55% less pollution as compared to those in autos.
Air pollution at public places: Delhi
Jayashree Nandi, Dec 11 2014
The air in which one breathes through the day may be far worse than what the government's pollution monitoring. Because we often spend long hours near emission sources--on footpaths, along heavily congested roads, in an auto rickshaw in peak traffic and even in parks during morning walks. To assess what our real exposure may be like, TOI, in association with Centre for Science and Environment (CSE), spent a day monitoring hourly PM 2.5 (fine, respirable particles) on CSE's portable air quality monitoring device in front of schools, hospitals, shopping areas and traffic cop booths.
The idea was to understand what kind of air pollution levels children on their way to schools or patients outside hospitals may be exposed to. The hourly PM 2.5 averages logged at these locations were compared with the ambient air quality monitored by Delhi Pollution Control Committee (DPCC)'s monitoring stations near the locations.
The results were very disturbing -outside Mother's International School on Aurobindo Marg, for instance, the average for 8 am to 9 am was 718 micrograms per cubic metre! While there is no official safe standard for an hourly average, the 24-hour average for PM 2.5 in India is about 60 micrograms per cubic metre. The machine-TSI DustTrak DRX Aerosol Monitor 8533 showed peaks up to 800 micrograms per cubic metre, about 13 times the daily standard. During the same period, DPCC's RK Puram monitoring station recorded an hourly average of just 325 micrograms per cubic metre.
Inside All India Institute of Medical Science (AIIMS) campus, between 9.10 am and 10.10 am, the hourly average was 493 micrograms per cubic metre. Considering that patients with low immunity go to the hospital, they may be exposing themselves to more complications in such conditions.
As it got warmer and sunnier, PM 2.5 concentrations started plunging. At RK Puram, in front of Delhi Public School, the hourly average was 248 micrograms per cubic metre and later at Saket, in front of a shopping mall, the concentration was about 178 micrograms per cubic metre.
The exercise of monitoring exposure levels through the day also revealed the diurnal variation in pollution levels with air quality improving considerably in the afternoon (1 pm to 4 pm), especially if it is sunny and warm. The air quality started declining once again after 4.30 pm. This exercise also revealed that areas with a smooth but less vehicular traffic can have relatively much better air quality . In front of Dr Ram Manohar Lohia Hospital, for instance, traffic flowed smoothly . Here, the PM 2.5 concentrations ranged between 100 and 180 micrograms per cubic metre, far lower than other locations.
Government pollution monitoring agencies have claimed that such exposure monitoring may be “unscientific“ as such devices are mainly meant for “industrial“ projects and that there is no official standard for hourly readings. “Both pieces of information are valuable. The legal standard is indeed based on daily average concentrations measured at a fixed location. As our research demonstrates, air pollution levels in Delhi vary substantially with time and place, depending on where one is. In many locales, like in traffic, particulate matter levels are much higher than what official monitors indicate,“ said Joshua Apte of Lawrence Berkeley National Laboratory , who has done similar research in Delhi.
Air pollution inside homes, 2018
As Delhi’s air quality deteriorates by the day, you may be using masks to avoid inhaling the toxic air during your commute. Once you enter your workplace, the mask probably comes off, and you feel safer in the air-conditioned ambience. But are you truly breathing in safer air? Perhaps not. A recent study of 13 buildings in Delhi carried out by the Indian Pollution Control Association (IPCA) determined that while the levels of PM2.5, the microscopic, breathable particulate pollutants, was regulated, the air contained volatile organic compounds, bioaerosols and carbon dioxide beyond safe limits.
The study, conducted between January and September, found the use of devices like air purifiers helped contain PM2.5 pollution indoors, but harmful gases and compounds were largely ignored. The highest average PM2.5 level was recorded at 137 micrograms per cubic metre, over two times the safe standard, but relatively lower than the air outside. Multiplexes and hospitals had the lowest PM2.5 contamination, partly owing to the use of air purifiers.
Track the pollution level in your city
The study, however, cautioned that bioaerosols — particles of biological nature consisting of bacteria, fungi, viruses, microbial toxins, pollen and plant fibres — present indoors was a huge concern. While their presence in government buildings was discovered to be twice the safe level, they were, at 6,100 cfu/m3, over 20 times beyond acceptable limits in corporate offices. Similarly, high levels of volatile organic compounds were found in both residential and corporate complexes.
“People focus mostly on PM2.5 pollutants when VOCs and bioaerosols can be equally dangerous,” noted Priyanka Kulshrestha, head, research and communication, IPCA. “VOCs frequently contain carcinogens like benzene, while exposure to high bioaerosol levels can cause diseases, allergies, even cancer.”
The study also recorded high CO2 levels, almost twice the safe standard in corporate offices. This can affect concentration and lead to lower efficiency by increasing drowsiness and fatigue.
Kulshrestha recommended the introduction of indoor air purifying plants and proper ventilation to help improve indoor air quality. “Windows in an office should be opened at regular intervals to bring down the concentration of VOCs or gases and to lower CO2 levels,” she said. “To prevent bioaerosols, mouldy walls and vents need to be cleaned regularly. VOCs can be controlled with the use of chemicals and sprays.”
Home truth: Air is probably as bad inside
However, Arun Sharma, professor at the University College of Medical Science, suggested a balance in these basic measures. “If you keep the windows open for too long, the PM 2.5 level could become extremely high. Improving ventilation should not mean windows and vents stay open a too long time,” said Sharma.
Experts said the symptoms of problems caused by indoor pollutants include irritation in the skin, eyes or body and often coughing and wheezing. A high CO2 level makes one feel tired and sleepy.
Delhi: air and noise pollution
See graphic :
Delhi, air and noise pollution
2016 vs. 2017: air quality
In Terms Of AQI, 2016 Didn’t Have A Single Good Day: CPCB
Even though Delhi experienced a deadly smog episode spanning more than a week in November, a recent report by the Central Pollution Control Board indicated that the overall air quality might have improved in 2017 compared to 2016. In a note, “significant achievement 2017”, CPCB scientists listed steps that the pollution watchdog took last year and displayed monthwise air-quality data, indicating that while the number of “satisfactory” and “moderate” days increased in 2017, “very poor” and “severe” days came down.
The note also claimed that there was no high-level coordination in 2016, but, in 2017, there was a review of the situation by the PMO, secretary (Union environment ministry) and the chief secretary. To back this, CPCB noted that the number of continuous or real-time monitoring stations were increased from 18 to 38 in Delhi; another four were installed in Haryana, three in Uttar Pradesh and two in Rajasthan. It stated that there was now a 24X7 unified control room, which dealt with public grievances, forecast, remote-sensing data access, real-time data access and calculating a particulate matter-based AQI.
CPCB claimed that a 42-point action plan, which was developed in 2015 under the then environment minister, Prakash Javadekar, was implemented in 2017. At a review meeting in 2016, it was found that hardly any of the 42 points were implemented in 2016. Among other steps, CPCB listed formation of 40 air-quality monitoring teams, notification of construction and demolition waste norms, and a decision to leapfrog to BS-VI-compliant fuel in 2018 in the capital.
“Delhi is significantly impacted by meteorological factors. There is also intrusion of pollutants from the nearby areas.
The improvement we are seeing basically backs the fact that if we can control ground-level emissions, we will see some difference in air quality. In 2017, the onset of winter was late, but we still managed to see some improvement. Increasingly, the clear seasonal variations seen earlier are shifting and this also impacts air quality,” Dipankar Saha, head of CPCB’s air quality lab, said, adding that “multiple agencies had taken action to control air pollution in 2017 under the graded response action system”.
For the first time since May 2015 (when AQI mapping started), Delhi recorded two “good” air-quality days in 2017. Also, “very poor” days reduced from 97 in 2016 to 76 in 2017 and “severe” days came down from 26 to eight. “This basically shows that the duration, frequency and intensity of smog episodes will reduce if action is taken to control emissions. GRAP came into force last October, but some action was taken since January 2017 like the Badarpur power plant was shut for the entire winter and an environment compensation charge was imposed on trucks. Now, GRAP has ensured consistent action,” Anumita Roychowdhury, executive director, Centre for Science and Environment, said.
Last week, a top CPCB scientist had said that the agency might consider using advanced LiDAR (Light Detection and Ranging) devices to vertically monitor the air quality of NCR.
This year is likely to be even more eventful for those tracking how the capital fights air pollution because the oil ministry has promised to roll out BS-VI in Delhi in 2018.
“The moment you improve fuel quality, the emission control systems in the existing fleet will perform better, wear and tear will be less and PM emissions will be lower. But the maximum benefit will be felt when the automobile technology is advanced to support BS-VI fuel. SC has directed the environment ministry to notify the comprehensive action plan, which means long-term solutions will also be taken,” added Roychowdhury.
2013-17: Improvement in 2017
Need To Build On Marginal Dip By Taking Proper Steps: Experts
If agencies can manage to sustain their efforts towards curbing emissions, 2017 may prove to be a milestone year for Delhi in terms of arresting the trend of rising particulate matter levels.
Data released by the Central Pollution Control Board for its national air quality monitoring (NAMP) stations in Delhi showed that there was a minor decline in PM levels last year — the first time since 2013.
This data corroborated CPCB’s recent claim that PM levels were lower in 2017 than 2016 and 2015 in CPCB’s network of automatic monitoring stations, which are different from those monitored under NAMP. The NAMP network consists of Pitampura, Siri Fort, Janakpuri, Nizamuddin, Shahzada Bagh and Shahdara. These locations are manually monitored and considered as primary reference by CPCB for policymaking and tracking long-term trends.
CPCB also conducts chemical speciation of pollutants at these locations. The data (being compiled since 2001) showed a consistent rise in PM levels in Delhi — the annual average was in “critical” category for both PM10 and PM2.5 in nearly all years. Data shared by CPCB also showed that annual average nickel levels in the air were in “critical” and “high” categories in 2009 and 2010, and intermittently in years after that.
On December 13, the SC directed the Union environment ministry to notify a comprehensive action plan within two weeks to mandate short-, medium- and long-term measures for all sources of pollution with deadlines. But the ministry has neither notified the plan nor held any meeting with the SC-mandated EPCA to finalise the timelines.
“If this improvement has to be sustained, then it important that the comprehensive action plan is notified and implemented immediately,” said Anumita Roychowdhury, executive director, CSE. The improvement in 2017 may be a combination of factors — both emergency action taken under the graded response action plan and SC’s orders, such as imposing an environmental compensation charge on trucks in 2016. But experts pointed out that the PM levels were still 2 to 3 times the safe standard.
An ex-CPCB chairman said: “I don’t think we should take this minor improvement very seriously as PM levels are still way higher than the standard. Maybe, we can recognise their efforts when PM pollution meets the standard. Even though CPCB claims that NAMP data is used to guide policy, there is a large variation in data monitored by them manually and data recorded by automatic monitoring stations. I have doubts about the quality of CPCB’s monitoring infrastructure.”
Dipankar Saha, head of CPCB’s air quality lab, said: “Meteorology plays a very important role in Delhi. I don’t think the improvement in air quality was because of meteorological factors; in fact, they were worse than in 2016. The improvement may be a result of coordinated action by various agencies.” He added: “There is a delay in notifying the comprehensive action plan as we need to hold meetings and consolidate various action plans into one.”
Oct- Feb, 2016> 2017
Air quality in the capital and surrounding regions has shown sign of improvements this winter — bettering from severe and severe plus categories to poor and very poor. However, there is still a long way to go to combat air pollution in the long term, states an assessment report released on Wednesday by Environment Pollution (Prevention and Control) Authority (EPCA).
The SC-appointed body also lifted the “severe” and “very poor” category measures falling under the Graded Response Action Plan (GRAP) citing improvement in air quality, which has largely remained between “moderate” and “poor” over the last few weeks. EPCA also lifted the ban on diesel generators in the capital and allowed opening of Badarpur thermal power plant. However, the plant will be shut down completely by July 31.
“The air in the NCR is so polluted and toxic that all our combined efforts have reduced pollution merely from the severe-severe plus categories to poor-very poor,” said EPCA member Sunita Narain. She added that air pollution at this level was still hazardous even for healthy people and much more efforts were required to bring it down to the good and moderate levels.
The data from October 1, 2017 to February 25, 2018 pointed towards a slight improvement in the air quality as compared to the same time last year. An analysis of Central Pollution Control Board’s air quality index data showed that the number of days in the severe category decreased for each month in comparison to the previous year, except in January. In February, 16% of the days were in the moderately poor category, compared to 8% in the previous year.
The data of PM2.5 from the four major monitoring stations — Mandir Marg, Punjabi Bagh, RK Puram and Anand Vihar — showed little impact with pollution levels remaining high. The levels at hotspot areas, particularly Anand Vihar, also showed no signs of improvement.
“We must not lose the momentum in our fight for clean air and forget the fact that right to breathe is fundamental,” said Bhure Lal, EPCA chairperson.
2016>2017: limitations of WHO’s data
Several Measures, Including Graded Response Plan, Initiated in 2017
While Delhi’s air quality, according to the latest WHO database for 2016, is at its worst, pollution bodies and the environment ministry say it’s not a true reflection of the current reality because several measures and actions were taken in 2017, including implantation of the Graded Response Action Plan.
According to WHO’s database for 2016, Delhi was ranked at sixth position in the list. The average PM 2.5 levels were, however, recorded at 143 micrograms per cubic metre — the worst since 2010, when Delhi was ranked as the most polluted city in the world with an average concentration of 141 micrograms per cubic metre.
According to the Union environment ministry, the data for 2017 has shown an improvement since 2016 and 2018 so far has also fared better than 2016 — indicating cleaner air due to the efforts that were made in 2017.
“CPCB data based on Continuous Ambient Air Quality Monitoring Stations (CAAQMS) indicates that the annual average PM 2.5 concentration in 2016 was 134 micrograms per cubic metre and 125 micrograms per cubic metre in 2017. Similarly, for PM 10, the figures were 289 micrograms per cubic metre in 2016 and 268 micrograms per cubic metre in 2017. Therefore, even PM 10 levels came down in 2017 against 2016,” the ministry said in a statement on Wednesday.
According to the environment ministry, significant action was taken in Delhi-NCR in the past year, which included the formulation and implementation of Graded Response Action Plan, banning of pet-coke as fuel, strict surveillance of coal-fired plants, augmentation of air quality monitoring stations and formulation of a comprehensive action plan by the ministry of environment, which is further likely to bring an improvement in 2018.
Dipankar Saha, the former head of CPCB’s air laboratory, said that improvements took place in 2017 despite adverse meteorological conditions in that year. “The meteorological conditions, especially during winter in 2017, were much worse when compared with 2016. The air quality, however, showed an improvement due to strict implementation of GRAP and other measures on the ground,” Saha added.
CPCB officials said that AQI data for 2017 already showed improvements as compared with 2016, which is evident due to the work that has been put in. “There were more number of good, satisfactory and moderate days in 2017 than in 2016. The number of severe days also came down in 2017,” an official said.
Anumita Roy Chowdhury of CSE feels that while groundwork has been done in 2017, the focus needs to shift from one city to the national situation. “Urgent intervention is needed for implementing the National Clean Air Action Plan with a strong compliance strategy to meet clean air standards in all cities. It requires hard action,” said Chowdhury.
2016> 2018: Delhi-NCR’s air is cleaner
Focus Now On Ways to Curb Winter Pollution
The air quality in the National Capital Region has improved in 2018 compared with the last two years, Central Pollution Control Board (CPCB) said on Monday.
An improvement in PM2.5 and PM10 concentrations has been recorded this year except for two high pollution periods — in January and June.
The CPCB’s air quality index assessment during 2016-18 also suggests that the number of “satisfactory” air quality days has gone up, while there have been fewer “very poor” days this year.
Proper implementation of the graded response action plan, ban on pet coke and closure of the Badarpur power plant in winter may have led to the reduction in air pollution, CPCB officials claimed.
To sustain this improvement, CPCB plans to start action on tackling winter pollutants from September 15. Forty teams of CPCB officials will fan out across the city and report on emission sources to the Delhi government and central agencies.
Filters on roads, bus rooftops to clean air
CPCB Plans To Intensify Green Fight
The ministry of earth sciences is chipping in by developing an early warning system by October to prepare for pollution spikes. Forecast from Indian Meteorological Department is already being used.
Apart from directions to be issued to industries and brick kilns in NCR, a central package of Rs 1,100 crore for in situ crop residue management will ensure farmers can use machinery to mulch crop stubble through custom hiring centres, Prashant Gargava, CPCB’s member secretary, said.
CPCB visits to pollution hotspots, such as RK Puram, Anand Vihar and DTU may be intensified this year depending on pollution levels.
CPCB plans to utilise the Environment Protection Fund, which was created following a Supreme Court order in August 2016 when the court imposed a 1% pollution charge on sale of SUVs, to fund several pilot studies. Three of these pilots may be tested this year. Among them are WAYU air filters by National Environmental Engineering Research Institute which will be installed at five busy traffic intersections. These filters work like vacuum cleaners and also cause some turbulence to disperse pollutants. But they are effective only in a 20-30m radius and, so, CPCB will have to install as many as 57 such filters. WAYU filters were installed at traffic intersections in Mumbai earlier, but local reports suggest there was no discernible difference.
TOI had earlier sought responses from experts on investing in such technology to deal with ambient air pollution. Most scientists and experts were critical of the idea. They likened it to installing air conditioners to tackle global warming. Emissions, instead, should be tackled at source, they had said.
This time, CPCB also plans to utilise about Rs 20 lakh to install air filters on bus rooftops. When the bus moves, the air flows through the filters installed. Another pilot is to use certain chemicals that are dust suppressants at construction sites. According to CPCB officials, all these pilot projects have been approved by the department of science and technology after studying technical details for each project.
BS-VI vehicles: A strong opposition was mounted in the Supreme Court against a government proposal to allow car manufacturers a grace period to sell their BS-VI noncompliant vehicles in the country after April 1, 2020, with a lawyer saying the people were living in a “gas chamber” and even the foetus was getting affected by high pollution. The car makers, on the other hand, justified the grace period to sell their vehicles contending that India was leapfrogging from the BS IV emission norms to BS VI within a short span of time.
The arguments on the issue of air pollution in the Delhi-National Capital Region saw the lawyer, who is the amicus curiae assisting the court, also saying that the government cannot allow the citizens to die due to a health emergency.
The least, worst affected parts of Delhi; other Metro cities/ 2018
Crop stubble burning: The least and worst affected parts of Delhi
The position in India’s other Metro cities/ 2018
Most polluted areas in NCR
The twelve worst spots
Air pollution in Delhi- The twelve worst spots
Diurnal variations in Air pollution in Delhi
Need For More Localised Pollution Plan
Even when the winter sky appears blue, parts of Delhi now have smog-like air quality. If you live in an industrial or peripheral area like Jahangirpuri or Anand Vihar, you are breathing heavily polluted air every day.
Last year, Delhi Pollution Control Committee (DPCC) added many new air quality monitors, so that now there is one every 7-8km.
Data from this dense network shows not only a very high level of pollution but also a sharp increase in pollutants that were earlier within the limit.
For instance, nitrogen dioxide (NO2) is usually present in a higher-than-acceptable concentration in many of the new locations being monitored.
NO2 is a respiratory irritant that also contributes to ozone pollution, particulate formation, and smog.
Winter levels of NO2 have been above 100 micrograms per cubic metre at eight locations, as compared to the 24-hour standard of 80 micrograms per cubic metre. These locations are different from those with the highest levels of PM 2.5 (fine, respirable pollution particles). DPCC scientists said vehicles might be adding to NO2 pollution.
Data worrying, but govts still lax
Without the new monitoring stations, Delhi would appear to have better air quality this year as some of the earlier stations — RK Puram, Mandir Marg, Punjabi Bagh — within the city’s core are faring better, even if their levels of PM 2.5 and PM 10 (coarse pollution particles) are at least thrice the safe standard.
However, at 12 locations the monitors showed PM 2.5 concentrations more than five times the 24-hour safe standard. These areas — Jahangirpuri, Wazirpur, Mundka, Bawana, Ashok Vihar, Vivek Vihar, Nehru Nagar, Patparganj, Anand Vihar, Narela, Rohini and Dwarka — are either industrial or semi-industrial clusters, or lie on the city’s periphery. PM 10 levels were also found to be five times the 24-hour standard at nine of the 12 locations.
“We know that Jahangirpuri, Wazirpur, Vivek Vihar and Narela may be affected by emissions from industrial activity. Bawana and some other stations may be affected by open waste burning. But it’s difficult to say right away,” said Mohan P George, head of DPCC’s air quality division.
The data is worrying, but neither the Delhi government nor the Centre has made localised plans to deal with emissions. Last year, Environment Pollution Control Authority (EPCA), which was set up by Supreme Court, ordered the Delhi government to commission a survey of illegal industries located in residential and non-conforming areas. A lawyer who represents DPCC told TOI there are between 70,000 and 1 lakh such industries in Delhi.
DPCC is in a bind because issuing show-cause notices to these industries under the Air and Water Act will amount to recognising them. So the government is considering other ways to regulate them.
Besides NO2, Benzene has become a significant pollutant at Mundka, Jawahar Lal Nehru Stadium and Anand Vihar. On some days its concentration is 2-5 times the safe standard. Benzene is a component of crude oil and petrol that can be harmful even at trace levels. Apart from vehicle exhaust, evaporation from petrol filling stations can raise benzene levels. But most petrol pumps now have vapour recovery systems installed.
“NO2 is high in all high traffic areas and in some with industrial emissions. Benzene, on the other hand, is an air toxin. It should be removed from the environment and we need a different approach for it,” said Anumita Roy Chowdhury, executive director, Centre for Science and Environment (CSE), adding that localised monitoring is helping them target local sources of pollution.
It comes as no surprise that Sahibabad has been identified as one of the five most polluted areas in the National Capital Region by the Supreme Court-appointed Environment Pollution (Prevention and Control) Authority . This is because out of 356 air polluting industries in the city, around 200 are in Sahibabad alone.
“We have identified 356 air polluting industries in Ghaziabad, with more than half being in the Sahibabad area,“ said Ajay Sharma, regional officer of the Uttar Pradesh Pollution Control Board (UPPCB).
“We have also identified 21 industries in the city that run on pet coke and nine that uses furnace oil, the use of which has been banned by the Supreme Court. We have started issuing notices to these industries and by November 1, we will ensure they are sealed if they do not switch to other energy sources,“ he added.
EPCA chairman Bhure Lal -who visited Sahibabad on Tuesday -has identified a number of sources contributing to air pollution in the area and sought immediate remedial measures.
An official who accompanied Bhure Lal told TOI, “In Maharajpur area, construction debris was dumped in the open and the EPCA chair man told us to clear it. He spotted a number of places where waste burning was rampant and asked us to enforce the National Green Tribunal (NGT) ban.“
The district pollution board said it was taking these steps. “Between October 12 and 18, we fined and sealed 12 polluting industries while action was taken against four builders for dumping construction waste flouting NGT norms,“ said Sharma.
“In addition, we have recommended to the UPPCB for closure of the Carbon Continental factory near Crossings Republik along NH-24 after it was found to be flouting pollution norms,“ he added.
Ghaziabad has been listed by the Central Pollution Control Board as one of the biggest polluters, with PM10 hovering over 400 micrograms per cubic metre, four times above the safe level, for the past few days.
Sapna Srivastava, scientific officer at the state pollution board, said a more analytical approach “is the need of the hour to really understand the problem“.
Referring to a survey do ne by IIT-Kanpur last year for the Delhi region on various sources of pollution, Srivastava said, “According to the report, road dust accounts for 38% of pollution in Delhi, followed by vehicular pollution, which comes to around 20%, which I think holds true for Ghaziabad as well to a large extent.“
“Now if road dust has been identified as the primary source of pollution, we along with the civic and development agencies should come up with a comprehensive plan to tackle this issue,“ she added.
An experimental station being run by the Central Pollution Control Board to monitor some toxic trace gases shows the capital’s air doesn’t just have very high particulate matter levels, but is also laced with hazardous air pollutants, such as mercury and formaldehyde. But it’s too early to say if the levels being recorded at this experimental station are too high, simply because there are no standards in India for these air toxics yet. Experts, however, say they are dangerous even at “trace” levels.
CPCB had set up a continuous air quality monitoring station based on Differential Optical absorption Spectroscopy (DOAS) at Parivesh Bhawan, East Arjun Nagar. It released data from the station from 2011 to 2016.
The station monitors sulphur dioxide (SO2), ozone (O3), nitric oxide (NO), nitrogen dioxide (NO2), formaldehyde (FOR), benzene (BEN), toluene (TOL), p-Xylene(pXy) and mercury (Hg), most of which are categorised as air toxics in the US and in Europe. These are mainly gases, particles or aerosols present in the air at levels where they pose a hazard to human health and they include volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), heavy metals and aldehydes.
CPCB started monitoring them on an experimental basis to study whether the same technology can be used to monitor emissions at critically polluted areas like industrial clusters, thermal power plants or around, say, pesticide manufacturing units. Among the air toxins monitored here, there are safe standards set for both benzene and ozone—while O3 levels met the annual standard, the standard for benzene was breached in all years except 2016.
Unlike the US environment protection agency (EPA), India doesn’t have an air toxics programme. According to US EPA, these pollutants are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or adverse environmental effects which is why EPA monitors 187 such air toxics. They regulate air toxics from large industrial facilities as well as smaller sources.
On what could be the source for mercury or toluene being recorded by the CPCB station, Dipankar Saha, former head of CPCB air lab, said: “This is an experimental station. Scientists are still trying to understand and validate the data. The only reason this station was set up was because we wanted to see if the technology can be used for critically polluted areas without any difficulty.”
CPCB has, however, not started monitoring these hazardous air pollutants on a large scale despite their serious health implications. “We have been saying that India needs a separate air toxics programme because these are pollutants, which will have to be eliminated from air, they are carcinogens. The monitoring should be done in a more widespread manner on a long-term basis,” said Anumita Roychowdhury, executive director at the Centre for Science and Environment.
Phase I: 2016
Impact on traffic
The Times of India, April 7, 2016
Odd-even was of little use, says IIT study
A study by IIT Delhi reveals that vehicle speeds had increased 11am onwards during the first phase of the odd-even scheme. The maximum increase recorded was 9%. However, the average speed of vehicles reduced marginally between 6am and 11am at some locations when the road-rationing exercise was undertaken from January 1and 15. The study , “Evaluation of the effects of the 15-day oddeven scheme in Delhi: A preliminary report“, by researchers at Transportation Research and Injury Prevention Programme (TRIPP), IIT-D, also found a high compliance with the odd-even rule at four locations that were observed.
This apart, car-flow rates per hour on different roads decreased by 7-9%. There was almost a similar increase in the number of buses and autorickshaws and a significant rise in the number of two-wheelers during the fortnight, the study says. The air pollution benefits were not apparent because of meteorological factors and the authors of the study felt that data from six stations under the Delhi Pollution Control Committee (DPCC) was not enough to analyse the benefits of the intervention.
According to the study , car occupancy increased at all locations except one. The speed data was extracted by the team using google maps distance matrix API. It provides real-time travel distance and time between a pair of locations.
Despite an overall increase in the speed of vehicles during the period, Dinesh Mohan, a former IIT professor and the lead author of the study, suggested there were no reasons why the scheme should be continued. “Since there is no improvement in air pollution and the impact on congestion is so little and in fact, it al so increased at times, there is no reason to continue it other than gaining international publicity ,“ he said.
He added that motorcycle use had gone up during the odd-even period, which could lead to fatal accidents. On why the vehicle speeds had reduced in the morning hours, Mohan said people might have started early to avoid the rule that came into force from 8am onwards. The lower speeds co uld also be linked to higher number of buses, autos and two-wheelers, Mohan said.
A recent study by School of Planning and Architecture (SPA) found that the vehicle speeds at most locations had increased from 15 to 26kmph.It further said that the improvement in speed was higher during the non-peak hours and that morning peak traffic volume reduced by 8-16%. It had indicated that people's ex posure to air pollution had reduced during the period.
But the IIT study said that “it is possible that the decrease in emissions from cars may be offset by an increase in flow of other vehicles,“ adding that combined PM 2.5 emissions from buses, autos and two-wheelers was estimated to be 20% of the entire the transport sector compared to cars that alone contribute 16% of emissions. While studies by SPA and Central Road Research Institute (CRRI) as well as an evaluation by the SC-appointed Environment Pollution Control Authority (EPCA) have found reduced congestion and pollution exposure during the oddeven scheme, Mohan said such studies needed “technical, rigorous analysis“ and his team had “videographed everything“ because it's very easy to get cheated otherwise.
Phase II: 2016
Impact on traffic
The Times of India, May 13 2016
After the Delhi government's own report claimed that the second phase of the odd-even was successful, but marred due to schools being open, a report by the Central Road Research Institute (CRRI) suggests that even the impact on traffic was minuscle.
The report, which is based on a study carried out by the CRRI under Dr Staish Chandra, the director, during the odd-even fortnight, found a stark difference between the impact of the first odd-even fortnight and the second one, in April.
The study , which was conducted to measure the impact of the odd-even policy on traffic volume and speed characteristics on the road network, mapped two arterial roads of the city--Inner and Outer Ring Road--and compared the impact of the two phases.
Dr Kayitha Ravinder of CRRI said, “There is a significant difference in the impact on traffic volume and speed le vels of the two odd-even pha ses. While the scheme in Ja nuary had huge impact on the speed--it went up by 47% --the scheme in April saw the speed reduced to 23% on the Inner Ring Road and 14% on the Outer Ring Road.“ The le vels are measured against the traffic volume and speed cha racteristics of normal days.
It's not just speed levels which didn't show a signifi cant change. According to the study , which was carried out on April 28 and 29, the impact was felt on the traffic volume as well. “In phase II, the total traffic reduction was only around 10-12%. The reduction in car traffic was only 15%,“ said Dr Ravinder, who conducted the study . In contrast, the traffic volume reduced to 20% during the first phase, with the percentage of cars on road reduced to 30%. “This measure may give results in the short run but not in the long run,“ he added.
Impact on sale of petrol and diesel
The Times of India, Jun 03 2016
The tall claims of the government on the success of the oddeven scheme notwithstanding, data from oil companies show that the second phase of the plan didn't lead to a considerable decline in the sale of petrol and diesel in the capital.
The sale of petrol, in fact, rose from 1,16,315 kilolitres in March to 1,19,593 kilolitres in April. The dip in the sale of diesel, on the other hand, wasn't much either. Data from oil companies -IOCL, BPCL and HPCL -show that the sale of diesel was almost static at 1,35,110 in April. The figure for March was 1,35,340 kilolitres.
It was the searing heat, coupled with lack of adequate public transport options, which probably led to a higher number of people using private vehicles during odd-even 2.
The AAP government had showcased data from the first phase of the oddeven scheme to highlight its success, as the sale of both petrol and diesel had shown a visible decline during that period.
In fact, value-added tax (VAT) collections from the sale of petrol and die sel were lower by Rs 40 crore in January than December 2015.
However, April had quite a different tale to tell. It's likely that compliance to the vehicular restrictions was better in January because of the cold weather. Schools being closed for vacations also played an important part in a lower number of vehicles being on the roads.
IOCL, BPCL and HPCL together sold 1,52,272 KL of diesel in December. The sales declined to 1,39,411 KL in January but again rose to 14,5374 KL in February . They sold 1,14,538 KL of petrol in December, 1,05,525 KL in January and 1,07,542 KL in February.
The Aam Aadmi Party government notified a hike on VAT on petrol and diesel on January 19, four days after the first phase of odd-even ended. The rate was hiked from 25% to 27% for petrol and from 16.6% to 18% for diesel.
The government said it had rationalised VAT on the two fuels on the basis of a decision taken at a meeting of finance ministers of northern states for bringing uniformity in tax rates.
Pitfalls: NCR can't handle odd- even
Gurgaon, Noida and Gha ziabad will all have to implement the odd-even formula for private vehicles whenever it's rolled out next after the Supreme Court-appointed Environment Pollution Control Authority (EPCA) notified a graded response action plan for a pan-NCR implementation.
Odd-even will kick in if PM2.5 level crosses the “severe“ mark of 300 micrograms per cubic metre (gm3) or PM10 level crosses 500gm3, and persists for 48 hours.
The two previous instances of such a scheme being implemented were both by the Delhi government in 2016, with mixed results.
Neither the Haryana State Pollution Control Board (HSPCB) nor residents feel implementing an odd-even scheme in the city is a good idea. HSPCB officials have expressed that other measures, such as phasing out of diesel autos, could be more significant. “Phasing out of diesel autos or their regular monitoring would be more beneficial, as these are the primary source of air pollution in the city,“ said a HSPCB official.
Residents too seemed unsu re about the scheme's implementation. “Odd-even in Delhi made many people switch to car-pools or other means of transport. But I don't think it's possible in Gurgaon as the city has no public transport,“ said Sector 55 resident Satyendra Bajaj, who travels from his office in Cyber City to Sector 55.
His fears are borne out by the numbers. There are over 7 lakhs cars that travel on Gurgaon's roads every day , though only around 3.2 lakh (including 32,772 CNG cars) are registered in the city . To implement odd-even, authorities will have to make extensive arrangements of manpower and enforcement, as well as public transport. If one is to take a half of the 3.2 lakh cars out of the equation, it saddles the public transport system with at least 1.6 lakh extra passengers, if one person per car is factored in. The real number could well be double or more.
Around 1.5 lakh people travel on DMRC's yellow line between Samaypur Badli (Delhi) and Huda City Centre (Gurgaon). This will multiply manifold when the scheme is implemented. And it will have a cascading effect elsewhere. With only 34,000 autos, 500 bike taxis, 400 e-rickshaws and 62 city buses to cater to people who will be without a car on the odd-even days, chaos will spill over from Metro stations to bus and auto stops.
Garima Bhateja, who lives on Sohna Road and drives to her MG Road office, says: “Rapid Metro doesn't even cover 4km. City buses are rarely seen on roads, leaving us with only autos and taxis as options, both of which are costly and prone to over-charging. Thus, oddeven is not possible here.“
IIT studied hourly PM data in 2016, 2015
IIT Study Says Government Should Go For Staggered Timings If There's Another Round
A study on Delhi's odd-even trial has suggested that the road rationing scheme did improve air quality during the trial hours -especially during peak traffic hours -but those gains were lost due to heavy car and truck traffic during the nontrial hours between 8pm and 8am.
In addition to emissions from commercial vehicles, increased traffic at night after the odd-even hours may have led to the increase in the 24-hour average particulate matter (PM) values, reveals the study by IIT Delhi in collaboration with University of Surrey , University of Birmingham and others. It also found that the baseline concentrations --those excluding local emission sources such as vehicles estimated by IIT Delhi -at various locations were already high and masking the improvements from the odd-even trial.
The study used data from Delhi Pollution Control Committee (DPCC) to make their assessments for Anand Vihar, Mandir Marg, RK Puram and Punjabi Bagh. Except for RK Puram, all are near heavy traffic zones. It considered hourly averages for the oddeven days in January and April 2016 and the PM data for the same dates in 2015.
Researchers also found that meteorological factors like wind speed and direction played an important role. So while overall PM levels may have been higher during the odd-even phase in 2016 compared to same dates in 2015, it doesn't mean that the scheme failed to make a difference.“Observations clearly indicate that the comparison of the trial periods... will be affected by different background concentrations. Therefore as a necessary step, we estimated the baseline (local site background) concentrations at our selected sites.“
Baseline PM concentrations at all of these locations are taken and subtracted from the actual hourly concentrations to arrive at the net concentrations that can be attributed to vehicles. The team found there was a reduction in both net PM2.5 and PM10 concentrations during January and April trial hours but concentrations were much higher during the morning hours of odd-even and non-odd-even hours. “This seems likely to be related to the time taken for dispersion of the pollutants emitted overnight. The effect of the oddeven hours during winter ranged from a minimal re duction of -2% to a maximum reduction of -44% during peak traffic hours across the studied sites. This effect was relatively larger during summer with the corresponding reduction of -2% to -74% for PM2.5 compared to the 2015 levels.“
Professor Mukesh Khare of IIT Delhi, co-author of the study , said, “If the government is considering implementing the scheme again, they should consider staggered timings so that there is no sudden jump in emissions.“
“The real gains can only be achieved by restricting the entry of heavy goods vehicles during night hours,“ said the study , adding that commercial vehicles contribute to nearly half of the PM10 emissions from the exhaust of on-road vehicles in Delhi.
This is the first study to have singled out vehicular emissions to assess the impact of odd-even. Based on data assessment of previous years, scientists arrived at a baseline for each of these stations. The baseline PM2.5 was found to be the lowest and the highest at 12 and 113 micrograms per cubic metres at RK Puram and Anand Vihar, respectively .
Before another round, measures should be taken to “enable either full source apportionment of the particulate matter, or as a minimum, measurement of chemical tracers for road traffic emissions“, the study concluded.
Results of the ‘odd-even’ experiments of Jan 2016, April 2016
See graphic, The results of the ‘odd-even’ experiments on level of pollution, congestion and commuting, January 1-15, 2016 and April 15-20, 2016
Rainfall and air pollution
July 2017- Jun 2018
Bad-air woes washed away, for now
Clean air, a cool breeze accompanied by an afternoon drizzle brought respite to residents as monsoon hits Delhi a day ahead from its normal schedule.
Pre-monsoon and monsoon showers washed away dust and pollutants, bringing down the air quality index (AQI) from ‘moderate’ on June 25 to three consecutive ‘satisfactory’ days. The Regional Meteorological Centre, Delhi, said there may be light showers daily for the next three to four days.
There may be marginally higher rainfall on July 1 and July 2, RMC meteorologists added. Monsoon has covered nearly entire northwest of the country a fortnight ahead of its schedule. “It usually reaches Delhi on June 29. This time it arrived on June 28. There will be light drizzle and cloudy skies for the next few days followed by a period of slightly higher temperature. Monsoon usually covers all of Rajasthan by July 15, but this time it has already covered Rajasthan, Haryana, Punjab and adjoining areas about 15 days ahead of schedule,” said Kuldeep Shrivastava, scientist at regional meteorological centre.
While it may not rain everyday through July to September, Shrivastava said one can expect high humidity between 75% and 80% on most days. Delhi receives about 90cm of rainfall between the two months.
IMD stated that rainfall has been observed in most places over Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Punjab, Haryana, Delhi, east and west Rajasthan and over east and west Uttar Pradesh. This year monsoon touched Kerala on May 29 — three days ahead of schedule.
The PM 2.5 concentrations in the city also fell from about 79 micrograms per cubic metres on June 25 to 34 micrograms per cubic metres on June 29.
Rainfall recorded at Safdarjung observatory till 6.30pm on Friday was about 8.4mm, at Lodhi Road it was 4.7mm and at 10.4mm at Ayanagar.
The maximum temperature was 35.6 degrees Celsius — 1 degree below normal, while the minimum was 27.9 degrees Celsius.
Remedial measures taken
2017: Water sprinkling (wet scavenging of pollutants)
Delhi government is yet again looking at water sprinkling to bring down pollution levels in the capital post-Diwali. Environment minister Imran Hussain, who on Tuesday asked all city agencies to be on warmode to combat air pollution, has stressed on sprinkling of water from high-rises as one of the measures.
“The minister held a meeting with the chief secretary, commissioners of north, south and east corporations, New Delhi Municipal Council chairman, environment, transport and power secretary, special secretary (industries), chief engineer (PWD), and other senior officials of different government agencies. He directed PWD and Delhi Fire Services to undertake water sprinkling, especially after Diwali, for settling the suspended dust particles,” a senior government official said.
However, this exercise had proven futile last year, revealed before and after pollution data of the area where it was conducted.
On November 15, 2017, nearly 75,000 litres of water was sprinkled from Vikas Minar, the tallest building in ITO, a congested and polluted office hub in the heart of the city. However, readings from Central Pollution Control Board’s air quality monitoring station at ITO showed that the measure had little effect on pollution levels. The level of PM2.5 — ultrafine particles that can penetrate deep inside our lungs — continued to rise even after the hour-long exercise.
From 106 micrograms per cubic metre (satisfactory category) at around 4pm, the level of PM2.5 in the region shot up to 129 micrograms per cubic metre (very poor category) by 5pm. By 11pm, it had shot up to around 227 micrograms per cubic metre.
Experts say wet scavenging of pollutants, as the method is popularly known, is effective only when the source of pollution is confined to a limited area and the pollution is short lived.
“The aerial sprinkling last year had very little effect. It is just a temporary measure to control pollution levels when it reaches alarming levels,” former air laboratory chief at the CPCB, Dipankar Saha, said.
SN Tripathi, coordinator of Centre for Environmental Science and Engineering at IIT Kanpur, said aerial sprinkling can help in a small area, but not a polluted city like Delhi, which has multiple emission sources. “There are other effective, long-term measures. If the government is doing it, there is need for some transparent results on how effective the exercise was and a mechanism to assess it,” he said.
Delhi government had in December last year also deployed an anti-smog gun, a device which sprays atomised water (tiny droplets of water) up to a height of 50 metres, creating an artificial mist, which is in turn expected to stick to air-borne pollutants and bring them down to the ground. However, when the device was tested at Anand Vihar, near a pollution monitoring station, it had little impact on air quality readings.
Last year, the government had also installed an “anti-pollution tower” under the Indraprastha Marg flyover, near ITO. This tower is fitted with exhaust fans to suck in polluted air. A machine inside the tower then removes nearly 90% of the particulate matter and spews fresh air out. Such purifiers are known to work indoors but in a city like Delhi, where there are multiple sources of pollution, they rarely help, experts said.
Successes in lowering pollution
Nov. 2017 better than 2016
Measurement of parameters- PM 2.5, mixing height, wind speed, temperature, relative humidity, November 2016 and November 2017
Conditions Were Worse Than 2016: CPCB
The meteorological conditions have been much worse in 2017as compared to the ‘peak’ period in 2016, said Central Pollution Control Board (CPCB), with measures like Graded Response Action Plan (GRAP) and other efforts on the ground helping control the pollution.
CPCB officials said Delhi actually witnessed a better November with lesser pollution this year despite both temperatures and mixing height — the height at which particulate matter disperses — being much worse as compared to the peak period last year.
CPCB data shows that in the peak period this year between November 7 and November 12, Delhi’s average temperature varied between 21.6 to 23.6 degrees Celsius as compared to 2016 when it was between 22.9 to 26.1 degrees Celsius. This in turn also affected the mixing height which was much lower this year as compared to last year — therefore trapping particulate matter closer to the ground and reducing wind speed. The mixing height was between 336 to 479 metres this year as compared last year when it ranged between 146 to 618 metres.
Dipankar Saha, head of CPCB’s air laboratory, said that this in turn also affected the wind speed which varied between 1 to 1.3 m/s this year. Last year, during the peak period between October 30 to November 7 when Delhi witnessed ‘severe’ pollution levels, wind speed was between 1 to 3 m/s.
“The mixing height was much lower this year and the wind speed was very calm. This makes it difficult for particulate matter to disperse easily and it stays close to the ground. Pollution levels, however, have been controlled this year much better than last year, largely owing to preventive measures like GRAP and all agencies being more aware and active on the ground,” Saha told TOI.
CPCB data during the same period also showed higher relative humidity this year which reached as high as 75% as compared to last year when it ranged between 47.8% and 63.3%.
Variations according to season, time
'Air quality: worst at night and early morning
Delhiites may be exposed to the worst air pollution at night and early morning, indicates a study by the Centre for Science and Environment (CSE). CSE chose eight people and monitored their exposure to pollution for 24 hours using a portable device. It also found that situation in the Lutyens' zone, where the rich and the powerful reside, is no better despite the greenery and sparse traffic. The study found PM 2.5 (fine, respirable particulate) levels to be the highest at night and during hours when these people go for morning walk. In some cases, even indoor air quality was extremely poor.
The study involved monitoring the personal exposure of Bhure Lal, chairperson, Environment Pollution (Prevention and Control) Authority (EPCA), a resident of Lodhi Estate, Harish Salve, senior Supreme Court advocate who lives in Vasant Vihar, Ashok B Lall, architect and resident of Civil Lines, Randeep Guleria, head of pulmonary medicine department at AIIMS, William Bissel, head of Fabindia and resident of Hauz Khas enclave.The group also had people who suffer from asthma--Bharati Chaturvedi who lives in Ravindra Nagar in central Delhi, head of Chintan, Kaushik Das Gupta, a journalist and Avikal Somvanshi, a research professional and cyclist.
The 24-hour average exposure of each individual was compared with the readings of the nearest monitoring station of the Delhi Pollution Control Committee (DPCC) which revealed that the real exposure levels were much higher than the official figures. Lal who lives in Lodhi Estate was monitored on November 12 to 13.
Asthmatics are already facing a tough winter. “I was having breathing problems.Doctors recently told me I am borderline asthmatic and may get better if I am in a city with lower pollution levels,“ he said. Sunita Narain, director general of CSE, said she had stopped going for morning walks.
“Our data shows that for a couple of years after introducing CNG the pollution levels had stabilized, but they started to rise steeply with the increase in the number of vehicles. Our soft options are over, we need tough measures now,” Narain said.
Delhi: December: Air Pollution
December 20, 2014 Jayashree Nandi
Air quality in the city deteriorated to “hazardous” levels with the US embassy’s pollution monitoring station advising people to “avoid all physical activity outdoors”. Even the Delhi Pollution Control Committee (DPCC)’s real-time air quality monitoring system showed the 24-hour average count to be over 315 micrograms per cubic metre on Mandir Marg alone, which is about five times the national safe standard. Besides, a layer of smog shrouded the city. What is worse, there are more such bleak days ahead.
According to System of Air Quality Weather Forecasting and Research (SAFAR) under the ministry of earth sciences, pollution will increase at an alarming level in the next few days with a daily average of over 200 micrograms per cubic metre. The low temperature and calm air are causing “inversion“ that can lead to pollution such as smog being trapped close to the ground. Such poor air quality may trigger respiratory problems among people with low immunity, the elderly and the very young. Doctors fear poor air quality may be doing more damage than just triggering a few wheezing episodes. Constant exposure to bad air is making Delhiites vulnerable to arrhythmias and ischaemic heart disease. Arrhythmia is a disorder characterized by irregular heart beat or abnor mal heart rhythm while ischaemic heart disease is associated with reduced blood supply to the heart.
Dr S K Chhabra, head of cardiorespiratory physiology department of VB Patel Chest Institute, says continuous exposure to high air pollution levels is like being exposed to second-hand smoke. Recently, he made a detailed presentation on this before pollution control agency officials from Saarc countries. Chhabra quoted an AIIMS study which found higher number of complaints and instances of hospitalization due to chronic obstructive pulmonary disorder (COPD) and coronary issues apart from asthma and other respiratory conditions during high pollution days. He also said exposure to diesel emissions causes allergic responses.
“Fine particulate matter and gaseous pollutants are significant risk factors for acute stroke death. Women and the elderly are most susceptible,” his presentation said.
Dr Ashwani Mehta, senior consultant cardiologist at Sir Ganga Ram Hospital also be lieves the rise in incidence of strokes and arrhythmias are linked to high air pollution levels. “The respiratory problems from bad air can affect the heart. Besides, air pollution can cause myocardial infarction or heart attacks. Unfortunately we don’t have much data in India that can directly relate air pollution with the incidence of heart attacks. But increasingly we are seeing young people having heart attacks. Women who you don’t expect to usually suffer heart attacks are increasingly reporting heart attacks. It’s a combination of issues but I think particulate matter is also to blame.” Oncologists are seeing a 1% to 2% rise in lung cancer incidence each year but again there is no documentation of how much of lung cancer incidence is linked to air pollution.
Dr Vinod Raina, director and HOD, oncology and haematology at Fortis Hospital, said there was a “slight increase in incidence of cancer among non-smokers. Otherwise, we need documentation to understand how much air pollution contributes to lung cancer.”
2015-18: Air quality during monsoons
Barring Sept, Other Months Worse Than Last Year
Despite good rains, the capital’s air during this monsoon season wasn’t as clean as the same period last year. The city did not have a single “good” air day during the season (June-September) that is generally the cleanest period of the year, while the monthly air quality index (AQI) failed to reach the ‘satisfactory’ category in any of the four months.
Barring September, which recorded the best AQI for the month in at least four years, air quality in the other three months of the season wasn’t as good as the same months in 2017, the Central Pollution Control Board’s data reveals. The average AQI in August was higher than in the past two years.
Last year, the monsoon season had seen two “good” air days — when the CPCB’s sixgrade AQI records readings were in the range of one to 50. It became a much talked about event and was seen, at least in part, as an outcome of the anti-pollution measures being taken in Delhi and NCR.
The two “good” air days were recorded in July last year. The average AQI recorded that month was 98 — the only instance in four years (2015 to 1018) when the average air quality had improved to the “satisfactory” category (AQI range of 51 to 100).
The hope that air quality during this year’s monsoon would match this figure — with more anti-pollution measures taken since then, particularly the environment cess on trucks entering the city — has not been realised.
There were a higher number of “satisfactory” air days this season at 52, as compared to 48 last year and 24 in 2016. However, CPCB’s data shows that the average air quality this monsoon remained in the “moderate” zone during three months while it was “poor” in June. The poor air in June can partly be explained by the dust incursion from the Gulf that led to “severe” air quality in the capital for three straight days, a rare occurrence for that month.
“One has to realise that the local environment both within the city and outside, as well as meteorological factors, which include wind speeds and direction, will continue to play a major role in determining Delhi’s air quality,” said Dipankar Saha, former head of CPCB’s air quality monitoring.
While rainfall plays a big part in clearing air pollutants during the monsoon season, the data reveals that higher amount of rain doesn’t always bring cleaner air. For instance, rainfall in July 2017 (170.5mm at Safdarjung) was much lower than what was recorded during the same month this year and in 2016, but the air quality in 2017 was significantly better.
2017, 2018: Sept 23-29
That all familiar ‘winter’ feeling may soon be returning to the capital with Delhi’s air quality deteriorating to ‘poor’ on the Central Pollution Control Board’s air quality index on Saturday, with a reading of 219 – just days after it was recorded as ‘satisfactory’ and even touched ‘good’ briefly, falling below an AQI reading of 50.
The sudden deterioration in air quality over the last few days has primarily been due to local conditions according to experts, with Delhi witnessing a ‘transition’ phase where the monsoon retreats and the wind speeds drop – resulting in PM 10 levels shooting up to almost 2.5 times on Saturday.
D Saha, former head of CPCB’s air laboratory said the change is a common occurrence around this time of the year, however things will start improving once wind speeds increase. According to CPCB’s central control room data, the average PM 10 levels at 6pm on Saturday to be 254 micrograms per cubic metre – almost 2.5 times the safe standard of 100 micrograms per cubic metre.
Meanwhile, with the pollution levels spiking over the last 48 hours, the Supreme Court-mandated Environment Pollution (Prevention and Control) Authority (EPCA) is all set to meet on Friday to work on implementing the Graded Response Action Plan (GRAP) which will kick start on October 15.
EPCA officials said the meeting will look at localised sources of pollution, with hotspots in Delhi like Anand Vihar and Mundka currently being analysed due to their ‘high’ readings.
“There is no evidence to suggest at the moment that crop burning is the reason for this problem. Wind speeds in Delhi and NCR have fallen to almost zero and locations on the outskirts of NCR like Gurgaon or Rewari are all in the ‘very poor’ range almost. In Delhi, locations like Mundka and Anand Vihar are also in the orange category, which is mainly due to localised pollution and we want to identify that and start action on it,” said Sunita Narain, member of EPCA and director general at Centre for Science and Environment.
Meanwhile action on polluting industries in Delhi is likely to start soon with the Delhi Pollution Control Committee’s deadline for industries to shift to ‘approved’ fuels to end on September 30. DPCC, in its notification on June 29, had issued a list of fuels that could be used in Delhi, which included LPG, CNG, PNG, Diesel, Petrol and aviation turbine fuel among others.
2017/18: not much seasonal variation, summers marginally better
Air In NCR From March To May As Bad As In Winter Months
Winter pollution in the national capital region may be deadly, but summer doesn’t give much respite either.
While dust storms from Rajasthan may have led to a sudden severe spike in particulate matter pollution in the capital on Wednesday, the Central Pollution Control Board recently released air-quality data for NCR cities, which showed only a marginal improvement over winter in the air quality index in summer months as they continued to record “very poor” and “poor” air quality even in March, April and May.
Gurgaon, Ghaziabad and Bhiwadi, besides Delhi, are suffering extremely high air pollution levels. None of the NCR cities, except Alwar, recorded a single “satisfactory” air day in March; Delhi saw one satisfactory day, Gurgaon two, Ghaziabad one and Faridabad recorded three satisfactory air days in April.
In comparison, Gurgaon recorded as many as nine and Bhiwadi had 10 “very poor” days. Even in May, Bhiwadi had 11 “very poor” and one “severe” air day, and Gurgaon recorded 10 “very poor” days.
Delhi, Gurgaon, Noida and Bhiwadi had no satisfactory days in May. Experts believe NCR needs a consistent summer plan. Summer pollution may exacerbate in the coming years depending on meteorological trends. For example, this year was particularly dry with few western disturbances raising dust and loose soil. “In 2014, there were several dust storms and this year, too, we saw 7-8 episodes. It’s difficult to say if it’s a trend. But this year dust was definitely high and conditions extremely dry,” Kuldeep Shrivastava, scientist at regional meteorological centre of IMD, said.
The IIT-Kanpur’s Comprehensive Study on Air Pollution and Greenhouse Gases in Delhi carried out between 2013 and 2014 did highlight that summer pollution in the capital is mainly a result of dust and fly ash. The average concentration of PM2.5 in summer season was around 300 micrograms per cubic metres against the acceptable level of 60 micrograms per cubic metres. The crustal component accounted for about 20% of total PM2.5. “This suggests soil and road dust and airborne fly ash are a significant source of PM2.5 pollution in summer.”
But there are no such source apportionment studies for other NCR cities where thermal plants, industries and massive construction activity before monsoon may be adding to the trouble.
Sachchida Nand Tripathi, head department of civil engineering, IIT-Kanpur, said: “Prima facie, this summer it appears like dust is playing a major role in increasing air pollution levels. But we have to analyse PM10 levels in relation to PM2.5 levels and wind direction data to understand how much are anthropogenic sources like road dust contributing to the summer problem. It needs to be studied.”
Anumita Roy Chowdhury, executive director, Centre for Science and Environment, said: “Windblown dust increases significantly in summer. IITKanpur also flagged solid waste burning and emissions from fly ash dumps. The problem is similar in other NCR cities.”
Jan air in 2017, 18, 19
In Contrast, City Had Seen Its Cleanest December Of Three Years In 2018
Delhi’s air quality in January was as foul as in the same month in 2018, and much dirtier than 2017. According to the data released by the Central Pollution Control Board, the average AQI for January 2019 was 325. It was 327 last year and 304 in 2017. The city recorded a much cleaner October-December compared with the same periods in the past two years.
This year, there were seven “severe” days in January compared with four in 2018 and none in 2017. But this year, there were also two relatively clean “moderate” days against none last year and one the year earlier. 2019 also recorded the best and worst days, with January 3 logging the worst AQI of 444 and 22, the cleanest of 104.
Dipankar Saha, former head of CPCB's Air Quality Lab, explained the AQI variation was due to the emission load and dispersion mechanism. “In unfavourable meteorological conditions, the pollutants accumulate and their concentration increases, raising the AQI,” he said.
The capital had witnessed its cleanest December last year in terms of air quality in the past three years. The average AQI for the month in 2018 was 360 compared with 369.5 in 2017 and 364 in 2016.
The October data showed an improvement in 2018 with an average AQI of 268.6 against 284.9 in 2017 and 270.9 in 2016. The average AQI for November too showed a dip in 2018. It was 334.9, a big improvement from 360.9 in 2017. The average AQI in 2016 was even higher and Delhi had then experienced 10 “severe” days and an average monthly AQI reading of 374.1.
According to Anumita Roy Chowdhury, head of air pollution and clean transportation programme at Centre for Science and Environment, said the comparatively high January average despite October, November and December showing relative dips in AQI indicated that the city was responsible for its own foul air. “Till November, we know stubble burning in the neighbouring states contributes to the toxic air we breathe. In January, this factor is missing and we breathe in what we emit,” she said. “We need more year-round, long-term actions to be put in place and properly implemented.”
Gufran Beig, director, SAFAR, said the overall air quality this winter has been much better with January also not faring too poorly, despite the low temperatures. “Air quality may have been impacted in January by the fall in temperature,” Beig pointed out. “Compared with the last couple of years, the conditions were more hostile for air quality, with a big dip in temperature. This can lead to a spike in pollution levels.”
Air pollution: Delhi