Delhi’s air quality dips; may slip further if crackers are burnt, say scientists

New Delhi : The air quality in Delhi plunged Thursday with the AQI remaining in the ‘very poor’ category at a figure significantly above that on Wednesday. The season’s first foggy morning was also recorded Thursday, according to the India Meteorological Department (IMD).
Thursday, Delhi’s overall AQI was at 382, with PM2.5 and PM10 as the main pollutants, according to the Central Pollution Control Board bulletin. It stood at 314 on Wednesday.
Both the Safdarjung and IGI Airport centres reported poor visibility in the range of 600 to 800 metre Thursday morning due to mist and fog and the visibility remained low in the 800 to 900 metre range all through the day, according to IMD scientists. This can be attributed to a calm weather and higher humidity and is likely to prevail till the morning of November 6. The SAFAR system has predicted that the air quality will fall further to the edge of the ‘very poor’ to ‘severe’ category by Thursday night even if there are no firecracker emissions. Bursting of firecrackers will result in further deterioration. Firecracker emissions, even 50% of last year, could mean that the PM2.5 levels will reach the ‘severe’ category by midnight Thursday, and will increase further Friday morning. AQI could possibly cross the 500-mark in case there are firecracker emissions, the forecast indicates. AQI in the 301 to 400 range is ‘very poor,’ while AQI between 401 and 500 is ‘severe.’ The contribution of stubble burning to pollutants in Delhi is around 25%, according to the SAFAR forecast. This, combined with very calm conditions, have resulted in a dip in the air quality. The contribution of crop residue burning is set to increase to around 35% on November 5 and further to 40% on November 6 and 7. As a 24-hour average, the AQI has already fallen to the ‘severe’ category at some monitoring stations. At the Anand Vihar station, at 5 pm Thursday, the average AQI over the past 24 hours stood at 401. The station at Alipur recorded a higher figure of 426, Bawana recorded 432, Chandni Chowk 401, Wazirpur 441 and Ashok Vihar 409