Firecrackers Behind for 80% of Post-Diwali Pollution in Delhi: Centre for Science and Environment Report

Delhi’s air quality took a sharp hit after Diwali, with firecrackers emerging as a major contributor to the post-festival pollution spike. According to estimates by the Indian Institute of Tropical Meteorology (IITM), fireworks accounted for more than 80% of the capital’s pollution load on November 9, a day after Diwali.

The findings, shared in the press release of the Centre for Science and Environment highlight how a few hours of celebrations can significantly worsen air quality in a city already struggling with pollution from multiple sources.

A separate IITM source-apportionment assessment found that firecrackers contributed 71.1% of Delhi’s PM2.5 concentration between 1 am and 9 am on November 9. PM2.5 refers to fine particulate matter that can enter deep into the lungs and may even reach the bloodstream.

Firecracker Emissions Surged After Diwali

The assessment showed a sharp rise in the contribution of fireworks to PM2.5 levels around Diwali. Firecrackers accounted for 43.4% of PM2.5 during the corresponding hours on November 8, compared with just 5.6% on November 7. Their contribution was 5.6% on November 5 and 9.3% on November 6.

The impact was also visible in pollution measurements across the city. PM2.5 concentrations at Jahangirpuri reportedly reached 4,985 micrograms per cubic metre at 3 am on November 9. Nehru Nagar recorded 2,808 micrograms per cubic metre. However, the latter figure was subsequently revised to 776 micrograms per cubic metre by the Delhi Pollution Control Committee (DPCC).

Interestingly, vehicles accounted for only 6.9% of PM2.5 during the November 9 assessment window. Secondary inorganic aerosols contributed 5%, while secondary organic aerosols accounted for 4.5%.

Also Read: Firecracker Smoke and Eye Irritation: Why Burning, Red and Watery Eyes are Common After Diwali

Why Did Pollution Remain Trapped Over Delhi?

Weather conditions also played a role in prolonging the pollution episode. Low wind speeds meant that pollutants remained suspended in the air for longer instead of dispersing quickly.

Delhi’s average Air Quality Index (AQI) stood at 376 on November 8, placing it in the ‘very poor’ category. It improved to 299 by 4 pm on November 10, moving into the ‘poor’ category, but rose slightly to 302 by 6 pm.

Favourable winds helped improve conditions, although the accumulated pollutants did not disappear immediately. Wind speed, direction, temperature and humidity all influence how pollutants disperse in the atmosphere.

What Does This Mean for Your Health?

A sudden increase in fine particulate matter can be concerning because PM2.5 particles are small enough to travel deep into the respiratory system. Exposure to high levels of particulate pollution can irritate the airways and worsen symptoms in people with asthma and other respiratory conditions.

Children, older adults and people with existing lung or heart conditions may be particularly vulnerable during severe pollution episodes.

Final Word

The findings also underline the difference between temporary pollution spikes and year-round sources. While firecrackers caused a sharp increase after Diwali, vehicles, industrial emissions, construction activity and road dust continue to contribute to Delhi’s air pollution. 

The post-Diwali spike is a reminder that festive celebrations can have consequences beyond the night itself, with pollutants continuing to affect the air people breathe in the days that follow.