Delhi's AQI Improves After Nearly Entering 'Poor' Category, Likely To Worsen Again After Oct 15

As winter chill begins to set in, the air quality in the national capital is likely to worsen again from Wednesday, the India Meteorological Department (IMD) predicted. The AQI is expected to be recorded in the “moderate” category on Monday and Tuesday, before slipping into the “poor” category for six days, starting Wednesday.

“The air quality is very likely to be in the Moderate category from 13.10.2025 to 14.10.2025. The air quality is very likely to be in the Poor category on 15.10.2025. The outlook for the subsequent 6 Days: The air quality is likely to be in the Poor category,” the IMD said in its bulletin.

The city’s air quality improved on Sunday, a day after it had nearly slipped into the “poor” category. The city’s average AQI stood at 167

(moderate) compared to 199 on Saturday, helped by steady winds blowing at 10–15 kmph.

However, stubble burning’s contribution to Delhi’s pollution rose slightly to 0.8% from 0.4% a day earlier, according to the Centre’s Decision Support System (DSS). The Early Warning System (EWS) under the Ministry of Earth Sciences forecast that the air quality will remain “moderate” from October 13–14, turn “poor” on October 15, and stay that way for nearly a week.

As per Central Pollution Control Board (CPCB) data, the capital last recorded “poor” air on June 11 with an AQI of 245. Since then, Delhi has witnessed 123 days of cleaner air — 77 “satisfactory” and 46 “moderate.”

Why Air Quality Worsens in Delhi In October

Experts said air quality typically worsens in October due to the retreat of the monsoon, lower temperatures, and the start of stubble burning and festive fireworks. Slower winds and cooler conditions cause “inversion,” trapping pollutants near the surface, while northwesterly winds carry smoke from Punjab and Haryana, peaking around early November.

The DSS estimated that vehicles contributed the most to PM2.5 levels on Sunday (19.8%), followed by emissions from Sonipat (9.2%) and Jhajjar (5.1%). Farm fires remain relatively low this year, with Punjab reporting 116 cases and Haryana 11 between September 15 and October 11, compared to 533 and 280, respectively, last year.

Delhi recorded a maximum temperature of 31.5°C and a minimum of 19.6°C on Sunday. The IMD forecast clear skies and cool northwesterly winds, with maximum temperatures rising to 34°C by Wednesday.

Environment minister Manjinder Singh Sirsa said Delhi has logged 199 days of AQI below 200 this year — nearly double that in 2016 — reflecting “real improvement on the ground.”