Diwali Air Quality Analysis In 11 Capital Cities

Pic Credit : Localpostit

Unseasonal rain ahead of Diwali made the high pollution levels of several capital cities such as Delhi, Mumbai and Chennai dip just ahead of the festival. But the Supreme Court’s firecracker ban was flouted in many places, and air pollution started to spike on the night of November 12th and touched hazardous levels in quite a few places.

NCAP Tracker analysed PM 2.5 (fine particulate matter) data for 11 capital cities, viz. Bengaluru, Bhopal, Chandigarh, Chennai, Delhi, Gandhinagar, Hyderabad, Mumbai and Patna, for the day before Diwali, the day of Diwali and the day after Diwali (till 12 pm) for the years 2022 and 2023.The data was sourced from the Continuous Ambient Air Quality Monitoring Stations (CAAQMS) of the Central Pollution Control Board (CPCB).

Key Highlights:

1. On November 11, 2023 – a day before Diwali this year – eight of the 10 capital cities analysed, viz. Bengaluru, Bhopal, Chandigarh, Chennai, Delhi, Hyderabad and
   Mumbai, had lower PM 2.5 levels as compared to October 23, 2022, the day before Diwali last year. For the same days, Gandhinagar, Kolkata and Patna had levels that were higher in 2023 than in 2022.
2. On November 12, 2023, that is, Diwali day, only three cities – Bengaluru, Delhi and Gandhinagar – had PM 2.5 levels lower than those on Diwali in 2022, that is, on October 24.
3. PM 2.5 levels on this Diwali and for the 12 hours after (till noon on November 13) were above the Central Pollution Control Board’s (CPCB) daily average ‘good’ limit of 30 ug/m3 in all the cities that were analysed.
4. Among the 11 cities, the highest average PM 2.5 level on the day of Diwali 2023 was observed in Patna. At 206.1 ug/m3, the level as over 13 times more than the WHO’s daily safe limit of 15 ug/m3.
5. On November 13 (from midnight to 12 pm), Delhi recorded the highest PM 2.5 average of 395.9 ug/m3 among all the cities analysed.
6. Bengaluru recorded lower PM 2.5 averages in 2023 as compared to 2022 for the day before Diwali, Diwali day and the day after Diwali. Additionally, on the day after Diwali 2023, it recorded the lowest PM 2.5 average among the 11 cities analysed in this report.
7. Among the 11 cities, the highest spike (recorded at 15-minute intervals) was seen in Delhi. It was at 999.5 ug/m3 at Pusa on November 13 at 1:30 am. Several other capital cities also saw extremely high PM 2.5 levels on this year’s Diwali and the following day (November 13), from midnight to 12 pm.
8. All cities saw PM 2.5 levels peak between midnight and 1:30 am on November 13, 2023.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy