A day after recording "severe" pollution, Delhi's air quality improved slightly to "very poor" category on Wednesday after wind speed picked up and dispersed pollutants even though the stubble fire count increased.
The overall air quality index of Delhi was recorded at 366 by the Central Pollution Control Board (CPCB).
An official with the Centre-run System of Air Quality Forecasting And Research (SAFAR) said the improvement in air quality can be attributed to increased speed of early morning winds.
"Early morning winds picked up, which came as respite and dispersed particles rapidly and pulled back air quality towards very poor range," the official said.
SAFAR further said AQI for next two days would remain in "very poor" range but with increasing trend.
"Air quality is likely to deteriorate on November 3 as a result of post westerly disturbances which are likely to hit over Western Himalayas today," SAFAR said.
"Stubble fire count increased but as upper wind speed is slow it will only impact Delhi air marginally. Surface winds are again turning to be calm and favourable for stagnation," it said.
Gurgaon recorded "severe" air quality at 416, while it was "very poor" in Ghaziabad, Faridabad, Noida and Greater Noida.
Ten areas in Delhi recorded "severe" air quality while 23 areas recorded "very poor" air quality, according to the CPCB data.
On Wednesday, PM2.5 was recorded at 215. Fine particulates can be a matter of more serious health concern than PM10.
The PM10 level (particles in the air with a diameter of less than 10 micrometres) in Delhi stood at 370, according to the CPCB data.
On Wednesday, regional factors such as stubble burning contributed to 22 per cent of PM2.5 pollution in the national capital, according to SAFAR.
An AQI between 0 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'.
A thick pall of haze continued to engulf the national capital, and according to authorities, it would continue to hover over the city for the next three days.
On Tuesday, the city recorded the worst air quality of the season after pollution level turned severe at 401, prompting authorities to ban construction activities along with halting operations of industries using coal and biomass as fuel between November 1 and 10.
The Supreme Court-appointed Environment Pollution (Prevention and Control) Authority is considering regulating use of private vehicles if the pollution level in the national capital deteriorates.
It has urged Delhiites to use public transport for the first 10 days of November when the air quality of the national capital is expected to further deteriorate.
