India's air quality crisis: 10 most polluted and cleanest cities revealed - TN town records best AQI

A palpable divide between northern and southern India has been laid bare by the latest air quality data, with cities in the National Capital Region (NCR) and Uttar Pradesh dominating the list of the country's most polluted, while Tamil Nadu towns boast the cleanest air.

According to a 24-hour average data compilation by the Central Pollution Control Board (CPCB) as of 4.00 PM on Monday, November 24, 2025, the air quality crisis in the north remains acute. The report, cited by The Indian Express, shows Hapur in Uttar Pradesh recorded a ‘severe’ Air Quality Index (AQI) of 416, the worst in the nation.

The data reveals a concentration of hazardous air in the north, with six cities from Uttar Pradesh featuring in the top ten most polluted list. Following Hapur, Noida (397) and Ghaziabad (396) recorded AQI levels in the high ‘very poor’ category. Delhi NCT itself registered an AQI of 382, also categorised as ‘very poor’, with PM2.5 as the primary pollutant.

The NCR and surrounding areas continued to show alarming readings. Greater Noida (382), Charkhi Dadri in Haryana (366) and Bulandshahr (356) all reported ‘very poor’ air, as did Meerut (350), Manesar in Haryana (342) and Baghpat (330).

In response to the deteriorating conditions, authorities have moved to implement stricter measures under the Graded Response Action Plan (GRAP) in the national capital, advancing several pollution-control initiatives.

In stark contrast, the south and north-east of the country presented a far healthier picture. Ariyalur, a town in Tamil Nadu, recorded the country's best AQI at a mere 13, which falls firmly in the ‘good’ category. The state of Tamil Nadu demonstrated a remarkable clean air dominance, securing eight spots in the top ten list of cities with the best air quality.

Ooty (15), Karur (16) and Tiruchirappalli (16) followed closely behind Ariyalur. Thanjavur and Shillong in Meghalaya (northeast India) both shared an AQI of 17. Other Tamil Nadu towns including Perundurai (21), Tirupur (22) and Salem (22) also featured, alongside Mangalore (25) and Davanagere (26) from Karnataka.

The AQI scale, which categorises air quality from ‘good’ (0–50) to ‘severe’ (401–500), underscores the significant health implications and environmental challenges faced by residents in different parts of the country.