New Delhi, March 6 Ghaziabad was the most polluted city in India during the winter season in 2025-26, followed by Noida and Delhi, according to an air quality analysis by the Centre for Research on Energy and Clean Air (CREA).
At least 204 out of 238 Indian cities with sufficient monitoring data recorded average winter PM2.5 concentrations above India's National Ambient Air Quality Standards (NAAQS), up from last year's 173 cities, the CREA analysis said.
The analysis was based on Continuous Ambient Air Quality Monitoring Stations (CAAQMS) data from the Central Pollution Control Board (CPCB) from October 1, 2025, to February 28, 2026.
"Ghaziabad ranked as the most polluted city in India during winter 2025-26, recording an average PM2.5 concentration of 172 μg/m3. Noida ranked the second most polluted city, with an average concentration of 166 μg/m3. Delhi ranked third, recording an average PM2.5 concentration of 163 μg/m3.
"During the winter 2025-26 period, Delhi experienced 18 'severe' days, 87 'very poor' days, 24 'poor' days, 15 'moderate' days, six 'satisfactory' days, and only one 'good' day," the CREA analysis said.
Greater Noida, Bahadurgarh, Dharuhera, Gurgaon, Bhiwadi, Charkhi Dadri and Baghpat completed the list of the 10 most polluted cities, with Greater Noida ranking fourth and Baghpat 10th. Uttar Pradesh and Haryana accounted for four cities each among the top 10 most-polluted cities, along with one city each from Delhi and Rajasthan.
At the state level, Haryana recorded the highest number of cities where all monitored locations exceeded the PM2.5 NAAQS, with 24 cities breaching the standard. Andhra Pradesh (nine cities), Punjab (eight), West Bengal (seven) and Gujarat (six) also recorded exceedances across all monitored cities.
Rajasthan (33 of 34 cities), Maharashtra (30 of 31 cities), Bihar (23 of 24 cities), Uttar Pradesh (17 of 20 cities), Odisha (13 of 14 cities) and Madhya Pradesh (11 of 13 cities) also recorded high proportions of cities exceeding the national standard.
Chamarajanagar in Karnataka was the cleanest city in India during the winter of 2025-26, with an average PM2.5 concentration of 19 μg/m3. The 10 cleanest cities included eight from Karnataka and one each from Madhya Pradesh and Meghalaya.
"The comparison between the last two winters shows that widespread non-compliance continues, with more cities breaching the national standard in winter 2025-26 than in the previous winter.
"While the Commission for Air Quality Management (CAQM) has set PM2.5 reduction targets for the NCR region, similar nationwide PM2.5 reduction targets are needed with a stronger focus on controlling gaseous pollutants such as sulphur dioxide (SO2), nitrogen dioxide (NO2) and volatile organic compounds (VOCs), which contribute to the formation of secondary PM2.5 and ozone (O3), a major component of particulate pollution," said Manoj Kumar, India Analyst, CREA.
The air quality in winter 2025-26 also showed widespread exceedances among the cities covered under the National Clean Air Programme (NCAP). Of the 96 NCAP cities with adequate data, 84 recorded average PM2.5 concentrations above India's NAAQS, while all 96 cities exceeded the World Health Organization (WHO) guideline.
A similar pattern was observed among the non-NCAP cities -- of the 142 analysed, 120 recorded PM2.5 concentrations above India's national standard and all 142 exceeded the WHO guideline.
In the Indo-Gangetic Plain (IGP), 79 cities recorded sufficient monitoring data during winter 2025-26. Among them, 75 exceeded the national PM2.5 standard, while only four remained within the prescribed limit. In the National Capital Region (NCR), 28 of the 29 monitored cities recorded sufficient data coverage. None of the 28 cities complied with the national standard.