World's most polluted: Report places Delhi on top, with Lahore and Mumbai close behind

Air pollution

A new global report has cast a stark light on the severe air quality crisis gripping South Asia, with Indian and Pakistani cities constituting half of the world's ten most polluted urban centres.

According to data compiled by the Swiss air quality firm IQAir, Delhi has earned the unwelcome title of the world's most-polluted city, with Lahore in Pakistan ranked second.

The findings, which underscore a regional public health emergency, also place Mumbai and Kolkata within the top 10, at fifth and eighth respectively. Karachi in Pakistan secured the fourth spot, painting a bleak picture of atmospheric conditions across the subcontinent.

The global top 10 was completed by Kuwait City (Kuwait) in third place, Tashkent (Uzbekistan) in sixth, Doha (Qatar) in seventh and Canberra (Australia) and Jakarta (Indonesia) in ninth and tenth places respectively.

The concerning data emerged amidst heightened pollution levels in Delhi following Diwali celebrations. Despite a Supreme Court directive limiting the bursting of environmentally-approved "green firecrackers" to a two-hour window on Monday night, reports indicated that celebrations and their polluting aftermath continued well beyond the stipulated time.

The capital's air quality deteriorated significantly, with 36 out of 38 monitoring stations recording levels in the ‘red zone’, indicating ‘very poor’ to ‘severe’ conditions. At 10 pm on the festival night, the city’s overall Air Quality Index (AQI) was registered at 344, categorised as ‘very poor’ and four stations reported AQI levels above 400, pushing into the ‘severe’ category. As defined by the Central Pollution Control Board (CPCB), an AQI between 301 and 400 is ‘very poor’, while 401 to 500 is ‘severe’.

Contributing factors to the capital's toxic haze were quantified by the Decision Support System (DSS), which attributed 15.6 per cent of Monday's pollution to transport emissions and 23.3 per cent to other sources, including industrial activity.

In response to the deteriorating conditions, the Commission for Air Quality Management (CAQM) had proactively enacted Stage II of the Graded Response Action Plan (GRAP) across the National Capital Region on Sunday. The measures under this plan are designed to curb pollution from various sources pre-emptively.