Delhi AQI remains ‘very poor’ but Grap 3 not invoked

Forecasts by the Centre’s Early Warning System for Delhi (EWS) also showed that Delhi’s air quality was expected to improve to the “poor” category

Delhi’s air quality deteriorated to the higher end of the “very poor” category on Sunday, but the Commission for Air Quality Management (CAQM) in NCR decided not to invoke curbs under Section 3 of the Graded Response Action Plan (Grap) due to a declining trend towards the evening.

A light layer of smog at India Gate on Sunday. (Sanchit Khanna/HT Photo)

Delhi’s 24-hour average air quality index (AQI) was 368 (“very poor”) at 4pm on Sunday, according to the Central Pollution Control Board’s (CPCB’s) daily bulletin, marking a rise of over 100 points from Saturday’s 4pm reading of 255 (“poor”). The Supreme Court set a revised threshold of 350 to invoke Stage 3 of Grap, down from the earlier threshold of 400. However, the AQI had dipped to 360 by 8pm, prompting CAQM to wait on implementing curbs.

“Delhi’s average AQI exhibited an increasing trend during the day...which prompted the CAQM subcommittee on Grap to call a meeting at 4pm to review the air quality scenario and forecast for meteorological conditions,” CAQM said in a statement, adding that the subcommittee noted that the average AQI for Delhi was on a declining trend and thus, to hold a second review at 8pm.

“The subcommittee noted that the average AQI of Delhi was exhibiting a downward trend and with better wind speeds forecasted for late night hours, there is a likelihood of the average AQI of Delhi to reduce further to around the threshold of 350 with time,” it said at 8pm, adding it decided against imposing Grap.

Forecasts by the Centre’s Early Warning System for Delhi (EWS) also showed that Delhi’s air quality was expected to improve to the “poor” category by Monday as wind speeds pick up. “The air quality is likely to be in the ‘poor’ category from January 20 till 21. The AQI is likely to be in ‘very poor’ on January 22,” the EWS said in its daily bulletin.

Grap Stage 3 was revoked on January 16, after Delhi’s AQI remained below 300 for a second consecutive day. Stage 3 involves measures calling for a ban on private construction and demolition, as well as restriction on BS-3 petrol and BS-4 diesel private four-wheelers.