Delhi has seen an unexpected improvement in air quality this year, offering a rare respite from the usual smog, haze, and toxic air that typically plagues the city. Data from the Central Pollution Control Board (CPCB) reveals that the capital experienced its cleanest air in nearly a decade during the first nine months of 2025.
From January to September, Delhi’s average Air Quality Index (AQI) was 164, the best since 2018, when it was recorded at 164. In comparison, the AQI was 178 in 2024 and 167 in 2023. The year 2020 was excluded from this study due to unusually low pollution levels during the COVID-19 lockdown.
Weather And Regulatory Impacts
According to the Commission for Air Quality Management (CAQM), two major factors contributed to the cleaner air: favourable weather
conditions and stringent pollution control measures. Higher-than-normal temperatures in January prevented pollution from settling near the ground, while a mild summer without extreme heatwaves and heavy rainfall during the monsoon helped clear the air.
Breaking Down The Numbers
The data further highlights that Delhi’s average AQI between July and September was only 91, marking the best figures since 2018. In the same period, the AQI was 103 in 2023 and 109 in 2018.
Significantly, there were no ‘Severe’ or ‘Severe Plus’ pollution days until September this year, unlike the three such days recorded in both 2024 and 2023. Additionally, 75 days in 2025 fell into the ‘Satisfactory’ category, a considerable improvement from 2018.
Delhi’s True Challenge Comes In Winter
Despite the current air quality relief, experts caution that the real test lies ahead in the winter months, when pollution levels often escalate to dangerous levels from October to December. Factors such as smoke and dust settling in cold air, stubble burning in neighbouring states, and firecracker smoke during festivals contribute to this seasonal spike. While Delhi residents are enjoying cleaner air now, the upcoming winter will be a critical period for maintaining these improved conditions.
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