Delhi's air quality deteriorated sharply on Sunday, 21 September 2026, with the capital recording its highest average Air Quality Index (AQI) in 62 days — a reading of 160 — as stagnant winds, the absence of monsoon rainfall, and local emissions combined to push pollution levels to a moderate-to-poor threshold. Meanwhile, the India Meteorological Department (IMD) forecast predominantly dry conditions across Delhi-NCR through Monday, with no significant rainfall expected in Delhi, Noida, Gurugram, Ghaziabad, or Faridabad.

Delhi's Worst Air Day Since July

According to the Central Pollution Control Board (CPCB)'s 4 pm bulletin, Delhi's average AQI stood at 160 — placing it at the higher end of the 'moderate' category. The pollution level climbed further during the night, reaching 165 by 10 pm. The last time Delhi recorded a comparable reading was 19 July, when the AQI stood at 171, also in the 'moderate' range.

The deterioration was rapid: Delhi's AQI had been 88 on Friday and 118 on Saturday before spiking to 160 on Sunday. PM2.5 and ozone were identified as the dominant pollutants driving the rise.

Six Stations Report 'Poor' Air Quality

Of the 45 active monitoring stations across Delhi, six recorded 'poor' air quality. The worst-affected locations were IGI Airport (264), Chandni Chowk (227), Okhla Phase-2 (219), Sirifort (210), Patparganj (209), and IIT Delhi (202).

Another 38 monitoring stations recorded AQI levels between 101 and 200, falling in the 'moderate' range. Delhi Cantonment was the sole station to report 'satisfactory' air quality, with an AQI of 81.

Weather Outlook Across NCR Cities

The IMD forecast mainly clear skies for Delhi on Monday, with the Safdarjung observatory likely recording a minimum of around 25°C and a maximum of nearly 35°C. Noida and Ghaziabad may see partly cloudy conditions, with temperatures ranging between 27°C and 36°C. Gurugram is similarly expected to see partly cloudy skies with temperatures between approximately 24°C and 36°C. No weather warning has been issued for any of the five NCR cities.

The dry spell is being attributed to the ongoing withdrawal of the southwest monsoon from parts of northwest India. The region is expected to remain largely rain-free over the coming days, which meteorologists and pollution experts note typically accelerates air quality decline in late September as wind speeds drop.

Context: A Clean September, Until Now

Delhi had enjoyed comparatively cleaner air through most of September 2026, recording 12 days of 'satisfactory' air quality and eight days in the 'moderate' range — largely because active monsoon rainfall and stronger winds helped disperse pollutants. Sunday marked the month's worst air quality day so far, and with the monsoon now retreating and temperatures remaining elevated, experts warn that the capital's annual winter pollution cycle could begin earlier than usual.

As the NCR prepares for a dry week ahead, residents — particularly those with respiratory conditions — are advised to monitor daily AQI bulletins issued by the CPCB.