Delhi has emerged as the sixth most polluted city in India for the month of October, according to the Monthly Air Quality Snapshot released by the Centre for Research on Energy and Clean Air (CREA). The report, based on data from Continuous Ambient Air Quality Monitoring Stations (CAAQMS), shows a sharp deterioration in air quality across the Indo-Gangetic Plain, particularly in the National Capital Region (NCR).
Dharuhera (Haryana) topped the list as the most polluted city, recording a monthly average PM2.5 concentration of 123 µg/m³ and breaching the National Ambient Air Quality Standard (NAAQS) limit on 77% of the days. It logged two ‘Severe’ and nine ‘Very Poor’ days during the month.
Following Dharuhera were Rohtak, Ghaziabad, Noida, Ballabgarh, Delhi, Bhiwadi, Greater Noida, Hapur, and Gurgaon—with four cities each from Uttar Pradesh and Haryana dominating the top 10, all within the NCR.
Delhi recorded an average PM2.5 level of 107 µg/m³, nearly three times higher than its September average of 36 µg/m³. Despite stubble burning contributing less than 6% of the capital’s pollution in October, the report stressed that the rise underscores the persistent impact of year-round emission sources and the need for long-term mitigation strategies beyond short-term seasonal measures like the Graded Response Action Plan (GRAP).
At the other end of the spectrum, Shillong (Meghalaya) was the cleanest city in India in October, with an average PM2.5 concentration of just 10 µg/m³. Other clean cities included four from Karnataka, three from Tamil Nadu, and one each from Meghalaya, Sikkim, and Chhattisgarh.
Out of 249 monitored cities, 212 recorded PM2.5 levels below India’s NAAQS limit of 60 µg/m³, but only six cities met the WHO’s safe daily guideline of 15 µg/m³.
he report also noted a shift in air quality distribution — the number of cities with ‘Good’ air quality (0–30 µg/m³) fell sharply from 179 in September to 68 in October, while those in the ‘Satisfactory’ range (31–60 µg/m³) rose from 52 to 144. Meanwhile, cities with ‘Moderate’ (61–90 µg/m³), ‘Poor’ (91–120 µg/m³), and ‘Very Poor’ (121–250 µg/m³) air quality categories also increased, signalling a nationwide decline in air quality as winter approached.