Firecrackers caused 71 per cent of Delhi PM2.5 pollution on Diwali night
Real-time scientific data shows firecrackers were a major pollution source in the capital for three consecutive days during the festival.
Firecrackers accounted for 71.1 per cent of Delhi's PM2.5 pollution between 1 am and 9 am on November 9, according to the Indian Institute of Tropical Meteorology (IITM). The festive source also contributed 43.4 per cent on November 8 and 29.8 per cent on November 10, according to reports from The Indian Express and Business Standard.
The IITM's AIRWISE system, which operates the Air Quality Warning and Integrated Decision Support System for Emissions, included firecracker emissions as a separate source for the first time. On November 9, vehicle emissions contributed 6.9 per cent to the PM2.5 levels, while secondary inorganic aerosols accounted for 5 per cent and secondary organic aerosols made up 4.5 per cent.
Delhi recorded an average 24-hour Air Quality Index (AQI) of 313 on Wednesday, which is in the 'Very Poor' category. The city's air quality is projected to enter the 'Severe' range by Friday, as the mixing depth is expected to shrink from 2,000 metres on Thursday to 1,400 metres on Friday.
Anumita Roychowdhury, Executive Director of Research and Advocacy at the Centre for Science and Environment (CSE), said that Diwali pollution is an annual tipping point but noted that elevated particulate levels before the festival show baseline pollution is higher than in previous years.
The Central Pollution Control Board (CPCB) clarified that hourly readings exceeding 1,000 micrograms per cubic metre are excluded from 24-hour AQI calculations. The board stated that the AQI is capped at 500 because any reading beyond that threshold remains in the 'Severe' category.