The concentrations of PM2.5 and PM10, two of the pollutants most closely associated with harmful air pollution, slightly increased this September compared with last year.

The cleaner PM2.5 levels also coincided with favourable weather conditions during the month.

The city has seen a sharp fall in fine particle pollution (PM2.5) over the past decade, dropping by more than half from 198.44 micrograms µg/m³ in 2015-16 to 91.7 in 2026-27, a decline of nearly 54% over the decade.

The report says Gurgaon’s PM2.5 pollution levels dropped by nearly 54% between 2015 and 2026, falling from about 198 to 92 micrograms per cubic metre. Most of the improvement happened before 2020, but progress has slowed sharply since then.

Faridabad’s annual average levels of PM10 — tiny dust particles harmful to health — remain more than 2.5 times above India’s safe limit. Even though the city has cut these pollution levels somewhat over the past five years, it has spent only about half of its allotted anti-pollution budget under the government’s clean-air programme.

Capital records AQI of 339 after 60-point jump in 24 hours; meteorologists forecast relief as western disturbance brings stronger winds

In 2025, Delhi met the national PM2.5 air quality standard on only 156 out of 365 days. This accounted for just 43 per cent of the year, with only four such days recorded during the winter season, which remained the most polluted period.

PM Emissions Still Far Higher Than National, WHO Cutoffs

CPCB cited estimates from the Indian Institute of Tropical Meteorology’s Decision Support System (DSS)

The Delhi government plans to restart a study on PM10 pollution sources, shifting focus from PM2.5, to better tackle air quality issues in the city.

Other NCR towns to the west, north and northwest of Delhi also recorded substantial contributions

On Diwali night, Gurgaon’s PM2.5 levels soared to 16 times the national limit as residents continued bursting crackers well past the Supreme Court’s permitted 8–10 pm window. The hourly concentration of PM2.5—a fine particulate pollutant linked to respiratory problems—rose sharply, with Sector 51 recording the highest at 949 micrograms per cubic metre around midnight. Despite restrictions, fireworks continued sporadically till 2 am in several neighbourhoods, including DLF phases, Sector 56, Palam Vihar, and Golf Course Extension. Residents complained that noise and smoke lingered for hours, reducing visibility. Officials said the city’s air quality remained in the ‘severe’ category for several days after Diwali.

Delhi experiences high levels of pollution throughout the year, not just in winter. Primary pollutants include dust and ozone, with significant PM2.5 and PM10 concentrations.