Delhi was ranked the sixth most polluted city in the country in October, behind neighbouring Ghaziabad and Noida, according to a study.

Dharuhera in Haryana was ranked as the most polluted city in October, with a monthly average PM2.5 concentration of 123 µg/m³, according to the Monthly Air Quality Snapshot released by the Centre for Research on Energy and Clean Air (CREA) on Tuesday.

It provided a comprehensive analysis of India’s air quality based on continuous ambient air quality monitoring station (CAAQMS) data.

The findings revealed a sharp deterioration in air quality across the country, with worsening conditions concentrated in the Indo-Gangetic Plain (IGP), particularly the National Capital Region (NCR), an official statement said.

Delhi ranked sixth with an average concentration of 107 µg/m³, three times higher than its September average of 36 µg/m³.

Despite stubble burning contributing less than 6 per cent of Delhi’s PM2.5 levels in October, the sharp rise highlights the impact of year-round emission sources and the need for long-term mitigation plans beyond short seasonal measures like the Graded Response Action Plan, it noted.