The GRAP comes into effect when the air quality hits the severe mark (450 and above). Experts attributed the improvement of air quality to the better wind speed of 0.90 m/s on Friday, up from 0.62 m/s on Thursday. Sun also put in an appearance and the better wind speed boosted air quality after the drizzle. Once the wind direction and speed is favourable to the region, air pollutants will disperse. “Depending on the wind speed is not a solution.

Source: Hindustan Times November 17, 2017 17:03 UTC