The air quality in the national capital remained poor for the sixth consecutive day on Monday with stubble burning accounting for seven per cent of the capital's PM2.5 pollution.
Air quality forecast agency SAFAR said the air quality is likely to improve marginally over the next two days due to winds coming from west and south-west direction.
The ministry of earth sciences' 'Air Quality Early Warning System' for Delhi predicted that PM2.5 and PM10 levels in the capital may get pushed to 250 micrograms per cubic meter and 398 micrograms per cubic meter, respectively, on Diwali night.
The acceptable limits for PM2.5 and PM10 concentration is 60 micrograms per cubic meter and 100 micrograms per cubic meter.
"The air quality is likely to deteriorate on November 5 and 6 significantly and may reach the upper end of the very poor category. PM2.5 to be the predominant pollutant," it said.
SAFAR said 3,971 farm fires were observed in the northwest region of Delhi on Sunday, the maximum this season so far.
"The share of crop residue burning emissions in PM2.5 is low due to unfavourable winds for transport," it said.
The Central Pollution Control Board's data showed the capital recorded a 24-hour average air quality index (AQI) of 281. It was 289 on Sunday and 268 on Saturday.
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".
According to the CPCB, agencies in the Delhi-NCR region have resolved just 11 per cent of air pollution-related complaints since October 15, when the Graded Response Action Plan (GRAP) comes into force to deal with the worsening of air quality in the region.
Only 47 out of 424 complaints have been resolved by agencies in Delhi and the NCR cities in Haryana, Uttar Pradesh and Rajasthan between October 15 and October 30.
Most complaints are related to construction and demolition activities, unpaved roads, road dust, open dumping of garbage and industrial waste and traffic congestion.
GRAP is a set of anti-pollution measures followed in Delhi and its surrounding towns according to the severity of the situation. It comes into force in mid-October when air pollution levels in the region start worsening due to unfavourable meteorological conditions and stubble burning.