Delhi was ranked the most polluted city in India in October, with an average PM2.5 concentration of 111 micrograms per cubic metre, according to a new analysis.

The analysis by the independent think tank Centre for Research on Energy and Clean Air (CREA) revealed that all the top 10 polluted cities in India in October were located in the National Capital Region (NCR).

These cities included Ghaziabad (110 micrograms per cubic metre), Muzaffarnagar (103), Hapur (98), Noida (93), Meerut (90), Charkhi Dadri (86), Greater Noida (86), Gurugram (83), and Bahadurgarh (83).

Delhi's October average was 2.5 times higher than September's average of 43 micrograms per cubic metre.

The CREA analysis further showed that stubble burning accounted for less than 10 per cent of PM2.5 pollution in Delhi in October. The increased PM2.5 concentration resulted mainly from contributions by year-round sources.

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