The air quality in the national capital inched towards "very poor" levels on Monday, as the mercury dropped to eight degrees Celsius, the season's lowest, making air colder and denser and hampering dispersion of pollutants. The air quality index of Delhi read 279 at 4 pm on Monday, up from Sunday's 250. The suburbs of Ghaziabad (325), Greater Noida (298), Faridabad (248) and Noida (275) also recorded an increase in pollution levels.
An AQI between 0-50 is considered 'good', 51-100 'satisfactory', 101-200 'moderate', 201-300 'poor', 301-400 'very poor' and 401-500 'severe'. An AQI above 500 falls in the 'severe plus' category.
Weather experts said the cold, dense air trapped pollutants near the ground and even a moderate wind speed of 16 to 18 kilometers per hour could not improve the air quality.
The minimum temperature is expected to drop to seven degrees Celsius over the next two days, said Kuldeep Srivastava, a senior scientist at the India Meteorological Department.
The wind speed will drop to 6 to 8 kmph by Wednesday and push pollution levels up, he said. The government's air quality monitor, SAFAR, said the AQI is predicted to dip to the lower end of the "very poor" category on Tuesday and Wednesday.
It said the fire count in UP, Haryana and Punjab was 300 on Sunday and the transport-level winds (north-westerly) were favourable for stubble plume intrusion. The share of stubble burning in Delhi's pollution is expected to be 10 per cent on Tuesday. It was four per cent on Monday, SAFAR said.