The air quality in Delhi was recorded in the 'poor' category on Sunday and is likely to deteriorate further amid a dip in the mercury and the wind speed. The city's air quality index (AQI) was 245 at 9 am. The 24-hour average was 231 on Saturday, 137 on Friday, 302 on Thursday and 413 on Wednesday.
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 maximum wind speed was 15 kmph on Saturday. It is likely to be 8 to 12 kmph on Sunday and Monday, according to the India Meteorological Department.
Winds are predicted to slow down on Sunday. Therefore, Delhi's air quality is likely to deteriorate further and remain in the "poor" to "very poor" category over the next two days, it said.
The minimum temperature was 7 degrees Celsius on Sunday and the maximum is predicted to settle around 26 degrees Celsius, the weather department said.
Calm winds and low temperatures trap pollutants close to the ground, while favourable wind speed helps in their dispersion.
The share of stubble burning in Delhi's pollution has also reduced significantly as the harvesting season has ended.
The contribution of stubble burning in neighbouring states to Delhi's PM2.5 levels was 4 percent on Saturday, 2 per cent on Friday and just 1 per cent on Thursday, according to the Ministry of Earth Sciences' air quality monitor, SAFAR.