Firecrackers caused 71 per cent of Delhi PM2.5 pollution on November 9
An assessment by the Indian Institute of Tropical Meteorology shows firecracker emissions became the primary source of fine particulate matter after Diwali.
Firecrackers accounted for 71.1 per cent of Delhi's PM2.5 pollution between 1 am and 9 am on November 9, according to an assessment by the Indian Institute of Tropical Meteorology (IITM), Pune, reported by Moneycontrol and Business Standard.
The contribution of firecrackers rose from 5.6 per cent on November 7 to 43.4 per cent on Diwali, November 8, before peaking on the morning of November 9. The share then dropped to 29.8 per cent on November 10.
During the same period on November 9, vehicle emissions contributed 6.9 per cent to PM2.5 levels. Other sources included secondary inorganic aerosols at 5 per cent and secondary organic aerosols at 4.5 per cent, according to the IITM assessment.
Monitoring stations recorded high pollution levels on November 9, with Jahangirpuri reaching 4,985 micrograms per cubic metre (µg/m³) at 3 am and Nehru Nagar recording 2,808 µg/m³.
Dr Sachin Ghude, Project Director of the Metro Air Quality and Weather Service at IITM, noted that this is the first time firecracker emissions have been listed as a distinct source in an official source-apportionment study.
The Central Pollution Control Board (CPCB) clarified that hourly readings exceeding 1,000 µg/m³ are excluded from AQI calculations, which can result in data gaps during extreme pollution events.