Delhi surpasses Lahore as world’s most polluted major city

India’s capital, Delhi, has overtaken Lahore to become the world’s most polluted major city, as hazardous air quality and thick smog reduced visibility across the city of nearly 20 million people on Friday.

According to Swiss air quality monitoring organisation IQAir, Delhi recorded an Air Quality Index (AQI) of 334, placing it at the top of the global pollution rankings. India’s Central Pollution Control Board (CPCB), however, reported an even higher reading of 403, categorising the city’s air quality as severe.

The difference between the two figures reflects variations in the AQI scales and measurement methods used by the monitoring organisations.

IQAir’s hourly data showed that Delhi’s AQI had improved to 208 by 11am Pakistan time. Meanwhile, Lahore ranked seventh among the world’s most polluted major cities, with an AQI of 155.

Dense smog covered several parts of Delhi, with cars and motorcycles navigating through reduced visibility. Videos from local media also showed pollution obscuring streetlights along major roads.

The latest rankings mark a shift in the regional pollution picture, with Lahore recording relatively lower pollution levels after remaining at the top of the global list for several consecutive days.

Air pollution typically intensifies across northern Pakistan and India during winter. Cold and stagnant atmospheric conditions trap vehicle emissions, construction dust and smoke from agricultural burning, allowing pollutants to accumulate near the ground.

A recent report by the Pakistan Air Quality Initiative (PAQI) highlighted the persistent pollution problem in Lahore. It found that the city’s average PM2.5 concentration was eight times higher than the World Health Organisation’s recommended guideline during the period covered by the assessment.

The report, released earlier this week, recorded an average PM2.5 concentration of 126 micrograms per cubic metre in Lahore. The city’s 24-hour National Environmental Quality Standards were exceeded on all 40 days for which valid monitoring data were available.

Despite the concerning levels, the average concentration was 11 per cent lower than during the corresponding period last year.

The assessment also found that the number of likely crop-residue fires in Punjab remained broadly unchanged compared with the same period in 2025.

Satellite monitoring detected 18,825 fires across Punjab, with approximately 89 per cent classified as likely crop-residue burning. November 1 recorded the highest number of daily detections, with 1,102 fires.

However, the report cautioned against attributing urban air pollution solely to agricultural burning. It said stagnant weather and limited atmospheric circulation also played significant roles in trapping pollutants and worsening air quality.