New Delhi, Dec 10 (IANS): Unfavourable weather conditions and a sharp drop in the minimum temperature (7.6 degree Celsius) in Delhi-NCR region led to "severe" air quality on Monday, and the toxicity is not going to improve for at least two more days.
"Delhi will have severe air quality till at least December 13. The situation might improve to 'very poor' with chances of light to very light rainfall in some parts of Delhi-NCR in a day or two," said Mahesh Palawat, Director at private weather forecasting agency Skymet.
He said the 'severe' situation might improve from December 14 with a forecast of dry north-westerly winds entering the national capital.
The Air Quality Index (AQI) of Delhi at 4 p.m. was 403 (severe) against 374 (very poor) on Sunday, on a scale of 0 to 500.
In the national capital region, the AQI of Ghaziabad was 430 on Monday evening, 433 in Greater Noida and 452 in Noida - all in the severe category since Sunday. Air Quality level in Faridabad deteriorated from 399 (very poor) on Sunday to 448 (severe) on Monday.
Meanwhile, Gurugram saw some improvement in its air quality as compared to Sunday's 'poor' (205) to 'moderate' (174) on Monday.
The major pollutant PM2.5, or particles with diameter less than 2.5 micrometres, also intensified and reached 'severe' levels over the day as easterly winds brought along moisture.
The average concentration of PM2.5 and PM10 in Delhi was 261 and 457 microgrammes per cubic meters on Monday. Across NCR, it was 257 and 441 units respectively.
"Currently, Delhi is receiving easterly winds which is bringing more moisture. Also, the winds are calm which is not allowing the pollutants to disperse. Moderate fog, caused due to high humidity and low temperature, is also keeping both gaseous and particulate pollutants near the surface unless sufficient rain occurs," said a forecast by System of Air Quality and Weather Forecasting and Research (SAFAR).
It, however, said that insufficient or moderate rain might deteriorate air quality as rain also leads to more moisture in the air.