As people burst crackers on November 8 to mark Diwali celebrations in Delhi, a thick haze engulfed the city. A study claims that firecrackers contributed the most as the air quality took a hit after midnight on Diwali.
According to an assessment of scientific data by the Indian Institute of Tropical Meteorology (IITM), Pune, firecrackers contributed to 71.1% of PM2.5 pollution from 1am to 9am on November 9, shortly after people wrapped up their Diwali celebrations. PM2.5 is fine dust, particles 2.5 micrometres across or smaller, and micrograms per cubic metre (µg/m³) measure how much of it is in the air.
Vehicle emissions, biofuel combustion, wood burning, and mineral dust were also contributing factors to pollution during the period but their contributions were negligible compared to those from firecrackers.
Deep Dive
What share of Delhi’s PM2.5 pollution came from firecrackers after Diwali?
Why did Delhi’s air pollution worsen after Diwali celebrations?
How did firecracker pollution levels differ before and after Diwali in Delhi?
Firecrackers' contribution to PM2.5 pollution on Diwali night was significantly higher than what was seen on days preceding it, according to the IITM study. Firecrackers are believed to have contributed to 43.4% of pollution on Diwali eve and only 5.6% from 1am to 9am on November 7. They accounted for over 29% air toxicity during the same period a day after Diwali.
Also Read: On Diwali night, Delhi's PM2.5 readings climbed towards 1,000, then went blank
{{/usCountry}}Also Read: On Diwali night, Delhi's PM2.5 readings climbed towards 1,000, then went blank
{{/usCountry}}As reported by HT earlier, even as Delhi turned into a gas chamber on Diwali night, none of the monitoring stations in the city recorded PM2.5 readings that went past 1,000.
Last Diwali, 29 of the 39 stations recorded at least one hour above 1,000, the highest 2,224 at NSIT Dwarka, according to a copy of CPCB's live feed kept by OpenAQ, an open-data platform.
Also Read: PM2.5 readings of 1K+ excluded from AQI: CPCB clarification after HT reports on ‘dark monitors’
The Central Pollution Control Board (CPCB) later clarified that the upper limit of these readings is capped at 1,000 micrograms per cubic metre (μg/m³).
The clarification came a day after HT reported that more than two-thirds of the Capital’s 59 air-quality monitoring stations went offline between 10pm and 6am on Diwali, when exposure to pollution was at its highest.
Several areas recorded an Air Quality Index (AQI) of over 400 in Delhi on the morning after Diwali and the average AQI at 376 in the 'very poor' category as of 7am. Sonia Vihar, Burari Crossing and Vivek Vihar were among some of the most polluted areas.
The Supreme Court had allowed the bursting of green crackers for limited hours on November 7 and 8, adding that a complete ban would be reinstated starting November 9.