Patna most polluted on the day of Diwali, Delhi a day after

Though rains ahead of Diwali brought some relief, pollution spiked on night of Nov 12


Data from various sources has shown that nine out of 11 capital cities in India recorded higher levels of air pollution post Diwali in 2023 compared to the previous year.

Though unseasonal rains ahead of Diwali made the high pollution levels of several capital cities such as Delhi, Mumbai and Chennai dip just ahead of the festival, it spiked on the night of November 12. This, despite the Supreme Court ban on firecrackers.

The National Clean Air Programme Tracker analysed PM 2.5 (fine particulate matter) data for 11 capital cities: Bengaluru, Bhopal, Chandigarh, Chennai, Delhi, Gandhinagar, Hyderabad, Lucknow, Mumbai and Patna. This was done for the day before Diwali, the day of Diwali and the day after Diwali (till 12 pm) for the years 2022 and 2023.

Analysis shows that on November 11, 2023 – a day before Diwali this year – eight of the 11 capital cities analysed—Bengaluru, Bhopal, Chandigarh, Chennai, Delhi, Hyderabad, Lucknow 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.

On November 12, 2023, that is the day of Diwali, only three cities – Bengaluru, Delhi and Gandhinagar – had PM 2.5 levels lower than those on Diwali in 2022 (October 24).

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.

Patna was the most polluted state capital with 206.1 ug/m3- a level over 13 times more than the WHO’s daily safe limit of 15 ug/m3. 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.

Bengaluru was the better performer and recorded lower PM 2.5 averages in 2023 as compared to 2022 for the day before Diwali, on the day of Diwali 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.

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.

The data was sourced from the Continuous Ambient Air Quality Monitoring Stations (CAAQMS) of the Central Pollution Control Board (CPCB).

Aarti Khosla, director, Climate Trends, said, “Data shows that the widespread bursting of crackers took away gains that were made due to the rains, thereby also bringing any useful impact.. for at least a two-three day period till the hazardous levels settle. A Supreme Court ban in Delhi NCR was flouted fully and shows that a different approach where the Centre and state must work together is needed.”

Experts are of the view that phasing out of the cracker industry is the only solution.

“While these are spikes that last only for a few hours or days, such high levels of air pollution add up to the exposure burden on human health, which is already high in Indian cities. Delhi and other major cities must not continue to bear the burden of public health in the name of hollow support for traditions. Instead, we can look at examples like Ayodhya, which broke a world record in lightning-up lamps,” said Khosla.

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