A recent analysis by the Centre for Research on Energy and Clean Air (CREA) has placed Delhi as the sixth most polluted city in India for October 2025, amid a broader decline in air quality across northern India’s Indo-Gangetic Plain.

The findings, based on real-time air monitoring data, show that pollution levels surged significantly throughout the month, with cities in the National Capital Region (NCR) and parts of Haryana topping the charts for poor air quality.

Dharuhera in Haryana emerged as the most polluted city in the country during October, recording an average PM2.5 concentration of 123 µg/m³. The report noted that Dharuhera exceeded the National Ambient Air Quality Standard (NAAQS) on nearly 77% of days, with two “Severe” and nine “Very Poor” air quality days.

Delhi, too, experienced a steep deterioration. Its monthly PM2.5 average rose to 107 µg/m³, nearly three times higher than September’s 36 µg/m³ reading. CREA’s data underscored how the capital’s pollution spike is not just a seasonal trend linked to stubble burning but a symptom of persistent, year-round emissions from vehicles, industries, and construction.

Interestingly, stubble burning contributed to less than 6% of Delhi’s particulate matter in October, suggesting that short-term curbs such as the Graded Response Action Plan (GRAP) are insufficient in addressing the broader pollution crisis.

Other highly polluted cities included Rohtak, Ghaziabad, Noida, Ballabgarh, Bhiwadi, Greater Noida, Hapur, and Gurugram — all clustered within the NCR region, indicating the area’s chronic air quality challenges.

At the other end of the spectrum, Shillong in Meghalaya recorded the cleanest air in the country with an average PM2.5 level of just 10 µg/m³. Cities in Karnataka and Tamil Nadu also featured prominently among the cleanest locations.

The report found that 212 out of 249 cities recorded PM2.5 levels within India’s NAAQS limit of 60 µg/m³. However, only six cities met the World Health Organisation’s far stricter daily standard of 15 µg/m³.

CREA’s study also highlighted a dramatic drop in cities with ‘Good’ air quality — from 179 in September to only 68 in October — underscoring the growing pollution crisis as winter sets in.

Experts warn that without sustained, long-term strategies targeting emissions from transport, industry, and construction, India’s recurring air pollution crisis will continue to threaten public health and the environment, particularly across the densely populated NCR.