For the first time this season, Delhi’s 24-hour average air quality plunged into the ‘severe’ category on Tuesday with an AQI of 424, according to the Central Pollution Control Board’s (CPCB) 4 pm bulletin.
PM2.5 was found to be the main pollutant. Of all 170 places in the country that were part of the CPCB’s air quality bulletin on Tuesday, Delhi recorded the worst AQI.
In the National Capital Region, Greater Noida and Faridabad also recorded AQI in the ‘severe’ category Tuesday. The AQI in Faridabad was 403, while it was 402 in Greater Noida. The air quality in Gurgaon, Noida and Ghaziabad remained in the upper end of the ‘very poor’ category on Tuesday.
The city’s worst air quality was at Ashok Vihar, Jahangirpuri and Wazirpur. All three monitoring stations recorded a 24-hour average AQI of 450 at 6 pm on Tuesday.
According to the CPCB, AQI between 401 and 500 is categorised as ‘severe’ and it “affects healthy people and seriously impacts those with existing diseases”. AQI between 301 and 400 is considered to be ‘very poor’.
Delhi’s AQI on Monday was 392 in the ‘very poor’ category, as per the 4 pm bulletin.
Delhi’s AQI slipped into the ‘severe’ category despite the contribution of stubble burning being lower on Tuesday than it was over the past three days. The contribution of stubble burning smoke to PM2.5 levels was around 14% on Tuesday, which is lower than the 22% recorded on Monday, according to an update from SAFAR (System of Air Quality and Weather Forecasting and Research). The highest contribution of stubble burning to PM2.5 levels in Delhi so far has been 26% on October 30.
The number of stubble fire incidents recorded in Punjab on Tuesday (1842) was also lower than the figure recorded on Monday (2131), going by data from the Indian Agricultural Research Institute (IARI). Haryana recorded 88 fire events on Tuesday, marginally higher than 70 recorded on Monday.
Due to the combined effect of stubble burning related pollutants, local emissions and weather conditions, air quality is likely to remain in ‘very poor’ or lower end of the ‘severe’ category for the next three days, according to SAFAR forecasting system.