Cloud cover, slow wind push Delhi's air quality to severe zone again

The air quality in the national capital slipped into the "severe" zone again on Thursday with unfavorable meteorological conditions allowing accumulation of pollutants.

Delhi's 24-hour average air quality index read 429. It was 370 on Wednesday.

Neighbouring Faridabad (428), Ghaziabad (347), Greater Noida (356), Gurugram (377) and Noida (408) also recorded a dip in the air quality.

An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".

The India Meteorological Department said the city recorded a minimum temperature of 13.4 degrees Celsius, four notches above normal, and a maximum temperature of 19.8 degrees Celsius, five notches less than average, due to a cloud cover.

Delhi's air quality this November was the worst for the month in seven years with the city witnessing severe pollution on 11 days and not a single day of "moderate" or "better" air quality, according to Central Pollution Control Board (CPCB) data.

Experts said though stubble burning remains a major factor behind the spike in the air pollution levels in the early phase of winter, local sources of emissions are the primary reason for highly polluted air in the city in the post-farm fire period.

According to an analysis by the Ministry of Earth Sciences' air quality forecast agency SAFAR, local sources accounted for 78 per cent of the air pollution in Delhi from November 22 to 26.