The air quality of the city inched closer to very poor category on Wednesday, chiefly owing to slower winds. The air pollution is expected to increase on Thursday and touch severe category in parts of Delhi on Friday, said government-run monitoring agency System of Air Quality and Weather Forecasting and Research (SAFAR).
On Wednesday, the average level of PM 2.5 deadly respirable particles, which is a chief pollutant was 150.4 ug/m3, more than 2.5 times the safe limit of 60ug/m3, as per Indian standards, in Delhi and NCR at 9 p.m., according to the Central Pollution Control Board (CPCB).
On Tuesday, the PM 2.5 level in Delhi and NCR had hit 625 ug/m3, which was more than 10 times the safe limit. The level was more than six times the safe limit (25 ug/m3) set by the World Health Organisation.
Delhis Air Quality Index (AQI) on Wednesday was 296, five points short of very poor, according to the 4 p.m. bulletin by the CPCB that is the average of the past 24 hours. An AQI between 0-50 is considered good and 51-100 satisfactory.
The contribution of stubble burning in neighbouring States to Delhis pollution was 8% on Wednesday and is likely to be 9% on Thursday, which is very less compared to the contribution of 44% earlier this season, SAFAR said.
The AQI is likely to marginally deteriorate to the middle-end of the very poor category by tonight [Wednesday]. It is likely to deteriorate further to the higher end of very poor category by tomorrow [Thursday]. The AQI has been forecast to touch severe category for some regions of Delhi on Friday. Overall AQI may still remain within very poor category, SAFAR said on Wednesday.