An AQI between 201 and 300 is ''poor'', 301-400 ''very poor'' and 401-500 ''severe''.
Pollution levels in the national capital remained in the "poor" category on Sunday morning.
At 9 AM, Delhi's air quality index (AQI) was recorded at 281, according to the Central Pollution Control Board (CPCB).
The AQI in adjoining areas of Noida, Greater Noida, Faridabad and Gurgaon was registered at 302, 297, 251 and 253 respectively.
An AQI between 201 and 300 is ''poor'', 301-400 ''very poor'' and 401-500 ''severe''.
It was a cold breezy Sunday morning with the minimum temperature settling at 14.5 degrees Celsius.
The weatherman has forecast that the maximum temperature is likely to settle at 29 degrees Celsius and there will be strong surface winds during the day. Humidity was recorded at 76 per cent.
On Saturday, the maximum and minimum temperatures were recorded at 29.8 degrees Celsius and 15.6 degrees Celsius respectively.