Air improves, Grap 4 ends

Continued rain and winds on Wednesday night led to dispersion of pollutants and therefore a clear weather on Thursday.

- Jasjeev Gandhiok

NEW DELHI: Stage 4 of the Graded Response Action Plan (Grap) was revoked on Thursday as a spell of light rainfall from late Wednesday to Thursday morning—caused due to a western disturbance—and strong surface winds dramatically improved the air quality in Delhi and NCR cities. The move comes a day after the Commission for Air Quality Management (CAQM) in NCR and adjoining areas imposed stages 3 and 4 of Grap due to a sudden decline in air quality due to meteorological factors.

On Thursday, Delhi's air quality index (AQI) improved to 302 ("very poor") at 4 pm from 386 ("very poor") recorded at the same time a day before.

The AQI had crossed the 400 ("severe") mark by 8 pm on Wednesday, but rainfall and winds in the intervening night dispersed pollutants. At 8 pm on Thursday, the AQI improved to 288 ("poor").

According to the Central Pollution Control Board (CPCB), an AQI between 0 and 50 is considered "good," 51–100 "satisfactory," 101–200 "moderate," 201–300 "poor," 301–400 "very poor," 401–450 "severe," and above 450 "severe plus."