Ahead of the impending winter chill, residents across the national capital region have received an encouraging environmental update. While early winter typically signals the onset of dense haze and deteriorating atmospheric conditions across Delhi, official monitoring suggests a notable improvement in the city's air quality trends throughout 2026. Data compiled by the Ministry of Environment, Forest and Climate Change alongside the Commission for Air Quality Management (CAQM) shows that Delhi registered an average Air Quality Index (AQI) of 102 in September 2026, marking the cleanest September the capital has experienced in the last five years.
Five-Year Trajectory Shows Sustained Improvement
A closer review of September AQI numbers over the past half-decade reflects steady progress in reducing baseline atmospheric pollution. In September 2022, the monthly average AQI stood at 104. The following year, in September 2023, the index rose slightly to 108, before settling at 105 across both September 2024 and September 2025. Dropping to 102 in September 2026 underscores an ongoing positive trend, with ministry officials noting that the overall pattern of improving air conditions has held steady throughout the current year.
Record Rise in Days with AQI Below 200
Between January and September 2026, Delhi also marked its highest tally of relatively clean air days in five years, measuring instances where the daily average AQI remained below the 200 threshold, classified as moderate or better. Over this nine-month stretch, Delhi logged 194 days with an AQI below 200. This surpasses the 187 such days recorded in 2025, the 188 days in 2024, the 193 days observed in 2023, and the significantly lower figure of 146 days registered during the corresponding period in 2022.
Significant Drop in Severely Polluted Days
The reduction in ambient pollution is further highlighted by a sharp decline in high-pollution episodes. According to official figures, only 79 days fell into the 'poor to severe' air quality category between January and September 2026. This represents the lowest count of heavily polluted days recorded in the five-year evaluation window. By comparison, such difficult air quality days numbered 127 in 2022, and stood at 86 days each in both 2024 and 2025, demonstrating a meaningful drop in severe atmospheric distress.
Fine Particulate Matter Concentrations Remain Lower
Readings for PM2.5, the fine particulate matter considered most hazardous to respiratory health, have also shown consistent containment compared to earlier benchmarks. Between January 1 and September 28, 2026, the average concentration of PM2.5 in Delhi stood at 69 micrograms per cubic meter. This matched the 69 micrograms per cubic meter level reported in 2025, while remaining significantly lower than the 81 micrograms recorded in 2024, the 73 micrograms observed in 2023, and the 80 micrograms per cubic meter measured across the same period in 2022.
Anticipating Cold Weather Constraints
With seasonal weather shifts imminent, falling temperatures, stagnant wind speeds, and other meteorological factors typically exacerbate pollution retention across the Indo-Gangetic plains during winter months. In response, CAQM has accelerated mitigation planning across multiple domains. The ministry noted that coordinated efforts alongside various regional stakeholders are being reinforced to implement stringent anti-pollution measures, ensuring that residents across Delhi-NCR benefit from cleaner ambient conditions as the seasonal transition sets in.
