Delhi’s air, already brimming with toxic pollutants ahead of Diwali, worsened with the festival fireworks, an analysis by the non-government organisation Centre for Science and Environment (CSE) showed.
CSE studied air quality data from the Delhi Pollution Control Committee and found that the levels of ‘fine particles’ – particulate matter less than 2.5 microns (a millionth of a metre) across, abbreviated as PM2.5 – had increased sevenfold since October 1, 2015, unto Diwali eve on November 10, 2015. The levels spiked further in several areas in the city during Diwali, too.
“There is a misconception that pollution due to Diwali crackers is a once-in-a-year event and so there is no need to worry about it,” Anumita Roychowdhury, CSE’s executive director for research and advocacy, told The Wire.
But the analysis found that the Diwali crackers added to the pollution in a city that was “already a gas chamber” by then, according to Roychowdhury. And then its health impacts remain for the days to follow, she added.
The official pollution data looks at the ‘ambient’, or general, pollution levels across the city, which is usually gathered at a height of six metres and often away from the sources of pollution. CSE looked at ‘exposure’ levels, which are closer to the nose and represent the air that is being breathed in. “Exposure levels are usually three to four times higher than ambient levels,” said Roychowdhury.
The spike in levels “leaves no room for additional pollution in the city, especially from crackers that not only push up the pollution but also lace it with deadly cancer-causing substances.”
Winter is coming has come
The CSE findings come within a week of the Indian government’s decision to set up a control room in the Central Pollution Control Board (CPCB) to undertake a daily review of air-pollution levels and monitor air-quality in Delhi and the National Capital Region.
Prakash Javadekar, the Union Minister of environment, forest and climate change, who announced the decision on November 6, had appealed to children to refrain from bursting crackers during Diwali. He had also urged Delhi’s residents to reduce pollution due to traffic congestions.
In February 2015, the Pune-based Indian Institute of Tropical Meteorology’s System of Air Quality and Weather Forecasting and Research (SAFAR) launched a mobile application to track air pollution in metropolitan cities. SAFAR had also forecast that, with cooler temperatures kicking in around Diwali in 2015 – earlier than when they did in 2014 – “there is enough moisture in the air, and atmospheric holding capacity is quite high for particles” emitted by firecrackers.
Additional conclusions: “In all likelihood, air quality during Diwali-2015 is going to be inferior to that of Diwali-2014 owing to cooler temperature and downward shift of inversion layer.” With humidity likely to be more than 96%, particles emitted from fireworks “will sit on water droplets and multiply, resulting in more particles in the suspended air itself.” This process – called secondary particle formation – was likely to have happened on November 12 and 13, causing a dense haze.
The SAFAR project’s director Gufran Beig said a similar spike in pollution was observed in Mumbai and Pune, where too the air quality had deteriorated alarmingly around Diwali time, with the corresponding index plummeting dramatically between November 9 and November 12. A health advisory accompanying the announcement said the post-Diwali level fell under the ‘poor’ category and that there is “increasing likelihood of respiratory symptoms in sensitive individuals. Children and elderly are at risk,” and people could generally experience some discomfort on account.
The sole silver-living: Pune’s 2015 pollution levels were lower than the 2014 levels.
Bullying past the limits
Beig is also an expert member of a WHO panel on framing guidelines for health impacts of air pollution and a member of the scientific advisory group of the Global Urban Research Meteorology and Environment (GURME) project of the World Meteorological Organisation (WMO). He clarified that “the health impact evidence for particulate pollutants are established for 24-hour averages and the ambient air quality standards are provided for 24-hour averages as per the WHO guidelines.”
“So the data for 24 hours needs to be compared with the standards and not the one-hour average or instant reading for deriving any health-related impacts. There are exceptions only for pollutants such as ozone, which is produced only in the presence of sunlight and is, therefore, measured over an eight-hour average.”
The National Ambient Air Quality Standards in India for PM2.5 is 60 microgram/m3 and that of PM10 is 100 microgram/m3. Compared to these numbers, CSE found that the average level of PM 2.5 in Delhi on October 1 was 76 micrograms per cubic metre. It rose to 327 micrograms per cubic metre by November 9 – a 4.3x hike. And the highest average was recorded on November 3 at 439 micrograms per cubic metre – 7x above October 1 levels.
Not surprisingly, the WHO ranked Delhi as the world’s worst city for air pollution in 2014. The CSE analysis further pointed out that, according to the CPCB as well as the Chittaranjan National Cancer Research Institute, Kolkata, every third child in Delhi has impaired lungs.
CSE next applied the official air quality index that was launched by India’s ministry of environment, forests and climate change in April 2015 and found a rapid increase in the number of days falling in ‘very poor’ and ‘severe’ categories over the last weeks of October.
No ‘good’ firecrackers
In fact, October had at least three days with moderate pollution; seven with poor air quality; and 18 days in the ‘very poor’ umbra. But there were no days with severe pollution levels.
November on the other hand has so far already shown seven days with severe pollution levels, and overall recorded higher pollution compared to the same period in 2014, the CSE analysis said. This is far worse than SAFAR’s relatively conservative forecast, that “Delhi is going to breathe ‘severe’ air at least for a day”. CSE found that the average for this period last year was 230 micrograms per cubic metre, and which since maxed out at 275 micrograms per cubic metre.
The peak pollution at the onset of winter has already overwhelmed the standards nine times over, with the highest value for PM2.5 over a 24-hour period recorded in east Delhi’s Anand Vihar on November 3: 565 micrograms per cubic metre.
Roychowdhury said the problem “cannot be tackled only with command and control measures,” but required strong public awareness campaigns aimed at reducing pollution due to bursting of crackers. Options could include restrictions on when to burst crackers, advisories on minimum distance to be maintained from homes, schools and hospitals for bursting crackers; and a ban on unregulated explosive substances.
Contrary to the belief that less noisy fireworks such as sparklers are safer compared to the louder ones, the coloured flames of the former include deadly toxic metals. “Crackers not only emit more of particulate matter, nitrogen oxides and sulphur dioxide but also spew cancer causing toxins,” Roychowdhury said. In fact, sulphur dioxide, which is usually at low levels in Delhi, spikes suddenly during Diwali.
“And even if the pollutants clear away from the source location due to weather conditions, they will settle elsewhere, especially water bodies, and enter the food chain.”