Delhi: Worst air quality on Deepavali in four years

Despite the blanket ban on firecrackers in the NCR, the air quality in Delhi on Deepavali and a day after the festival was in the ‘severe’ category. The readings were the worst in the last four years, as per the Central Pollution Control Board (CPCB) data.

The prime reasons were Delhiites bursting firecrackers, violating the ban, and Deepavali being in mid-November, which is late in the year (compared to the other three years), when the meteorological conditions are unfavourable.

The air quality index (AQI) of Delhi, a day after Deepavali was 435, while it was 297 in 2019, 390 in 2018 and 403 in 2017, as per CPCB’s 4 p.m. bulletin, which is an average of the past 24 hours. The AQI on Deepavali day this year was 414, while it was 312 in 2019, 281 in 2018 and 319 in 2017.

The level of PM2.5, a deadly pollutant, in Delhi-NCR was 469.3 ug/m3 at 6 a.m. on Sunday, which is about eight times the safe limit (60ug/m3) as per Indian standards.

According to government-run monitoring agency SAFAR (System of Air Quality and Weather Forecasting and Research), this year’s Deepavali day had the worst air quality in the past five years. But as per SAFAR, the air quality a day after Deepavali was the best in past five years, which is different from CPCB data.

“SAFAR uses data from fewer monitoring stations to arrive at the data compared to the CPCB and they take the value at a different time. This might have led to the difference,” a CPCB official said.

Explaining the high pollution this year, Anumita Roychowdhury, Executive Director of Centre for Science and Environment (CSE), a research and advocacy organisation in Delhi, said: “Deepavali usually happens earlier in the year and since it was late this year, the winter inversion condition was much severe. The wind speed and the mixing depth was less this year. Due to it, pollutants do not get dispersed easily. Last year, Deepavali was in October-end when conditions are not that bad. Certainly, this is one of the reasons for the high pollution this year.”

Due to these reasons, pollution on the days leading to Deepavali this year was also higher than last year.

“Effect of crop burning was also higher in Delhi till yesterday [Deepavali day]. With bursting of firecrackers, these two have contributed to the pollution,” Ms. Roychowdhury said.

SAFAR also said that there was a peak in levels of PM2.5 during the intervening night of Saturday and Sunday, probably due to bursting of crackers. “The magnitude of PM2.5 within the severe category is found to be more than predicted which tend to suggest that significant local additional emissions (probably firecracker related) during Saturday night... hourly average concentrations touched more than 1000ug/m3 at midnight,” SAFAR said.

The expert said that with data currently available, it is not possible to say whether the effect of firecrackers was more this year.

“The restrictions on firecrackers is very difficult to implement because we make that decision only a few days before Deepavali and there is no long-term planning. By that time, people have already manufactured crackers and it is available in the market. If the next Deepavali has to be different, then we should have a strategy and proper roadmap now itself, so that everyone can understand it, prepare better and it will be impactful in controlling pollution,” Ms. Roychowdhury added.

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Printable version | Jan 17, 2021 10:38:51 PM |

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