Winds, extended rain help slay pollutants

POST-DUSSEHRA Lesser use of crackers, with organisers opting for digital visualisation for effigy burning, also played a major role

day of Dussehra, the PM 2.5 value at Atnand Vihar — one of the major pollution hotspots in the city — increased from 29 micrograms per cubic metre at 5pm to 105 micrograms per cubic metres at 11pm.

The permissible standards for PM 2.5 and PM 10 are 60 and 100 micrograms per cubic metre, respectively.

“A slight rise in pollutants could be seen only for a few hours on the same day, post-effigy burning. The air quality at most monitoring stations remained in the moderate category. This has been possible because of a combination of factors including good weather conditions as well as allowing only use of green crackers and other dust-control measures being taken by the city government,” said Anumita Roychowdhury, executive directorresearch and advocacy, Centre for Science and Environment (CSE).

On Wednesday, Delhi’s air quality index (AQI) was 173 in the ‘moderate’ category as compared to 138 (also in the moderate category) a day before. Only Dwarka Sector 8 metro station recorded AQI at 308 in ‘very poor’ category from ‘moderate’ a day before.

“This year was the cleanest perhaps in the last ten years. There is no major dip so far because of the effect of rainfall in adjoining regions as well, which is clearing away the pollutants. There is no intrusion of dust from outside as well as from local factors, as rainfall and good wind has been washing it down. Efforts on the ground have to be maintained throughout winter season in order to prevent air quality from worsening,” said D Saha, former head of Central Pollution Control Board (CPCB) air laboratory.