On Tuesday, the day after Diwali, Delhi's air quality was the finest in seven years (October 25). This includes the epidemic years of 2020 and 2021. According to statistics from the Central Pollution Control Board, the AQI (air quality index) was 303 on Tuesday (CPCB). On Monday, Diwali, the temperature was 312. This signifies that the air quality was very bad on both days. An AQI of 301 to 400 is considered very poor. According to CPCB statistics, last year saw the worst post-Diwali air quality in Delhi since 2015, with an AQI of 462 recorded on the day after Diwali. This classified air pollution as 'severe.' Last year on Diwali, the AQI was 382. In four of the eight years since 2015, Delhi's air quality has deteriorated to 'severe' the day after Diwali.
REASON BEHIND THE CLEAN AIR?
On Diwali, it was windy, and Gufran Beig, SAFAR's original project director, noted that the wind speed helped reduce the collection of pollution. Furthermore, because Diwali fell early this year, the air is not yet chilly enough to trap pollution in the lower levels. Crop residue burning has also contributed nothing so far this year in Punjab and Haryana. The wind direction in Delhi, which has been westerly-southwesterly since Monday, has not been favourable for transporting stubble-burning smoke from the northwest, according to him.
According to a SAFAR forecasting system update, the percentage of stubble burning to PM2.5 levels in Delhi was approximately 5.6% on Tuesday. According to SAFAR statistics, the contribution of stubble burning to Delhi's air on Diwali day (November 4) last year was 25%, and 36% on the day following Diwali.
Anumita Roychowdhury, executive director of research and advocacy at the Centre for Science and Environment, identified many variables. "Diwali occurred early, with milder weather and before the strong inversion conditions set in." Wind speeds have been lower in comparison, and crop fires have not been as violent. "It's tough to say whether or not there were fewer firework emissions," she added.
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