Delhi Recorded Second Cleanest Post-Diwali Day Since 2015 Despite Widespread Fireworks, Spike In Stubble Burning. Here's Why

New Delhi: The air quality in Delhi remained within the "very poor" range on Friday morning despite widespread use of fireworks, and other factors like a spike in the share of stubble burning, and emissions from other local sources due to relatively warm conditions with reasonable wind speed and natural ventilation, according to experts. These factors contributed significantly in improving the air quality in city - which hit severe levels during midnight — to reach moderate levels by the afternoon next day, they said."The deep calm winter inversion conditions are yet to set in. Despite this, the month of October has also seen more poor and very poor days than previous years, even when the contribution of farm fires has been just around 1-3%, indicating a very high impact of local and regional pollution,” said Anumita Roychowdhury, executive director, Research and Advocacy at the Centre for Science and Environment (CSE), according to Times of India.High ventilation by winds of speed up to 16km/h and above-normal temperatures kept AQI within the "very poor" range, making it the second cleanest post-Diwali day since 2015.The clear skies seen day after Diwali was good in comparison to years like 2020 and 2021 — when air quality had plummeted to severe.While the bursting of crackers led to a significant dip in air quality on Diwali, stubble burning also made a huge difference in the city's PM2.5 level. According to the report, stubble burning soared to 27.61% on Diwali day (Thursday), compared to 8.4% on Wednesday and 1.8% on Tuesday."In addition to pollution from firecracker bursts, stubble burning incidents in Punjab are on the rise, signalling that post-harvest burning is ramping up and will likely exacerbate pollution in DelhiNCR over the next two weeks. Immediate intervention from authorities is crucial to manage this issue," Sunil Dahiya, founder and lead analyst, Envirocatalysts was quoted as saying by TOI.The city recorded AQI of 362 at 9am on Friday morning but the air gradually improved. By noon, it had improved to 354 on Friday, while the day’s average AQI was 339 against 328 on Thursday.According to the weather department, the wind speed was between 12- 16km/h until midnight on Diwali, which dropped to 3-7 km/h towards midnight but increased again on Friday morning, helping with ventilation and dispersal of pollutants."The air quality will remain an issue in the coming days due to an increase in stubble burning in the upwind states of Punjab and Haryana. According to the AQEWS, the AQI for the next seven days is expected to be consistently above 350 and will occasionally breach the 400- mark,” said Kar.