Delhi was the world’s most polluted major city on Saturday morning, according to Swiss group IQAir’s live ranking, as the Indian capital faced severe pollution forecasts a day before Diwali, the Hindu festival of lights.
IQAir ranked Delhi first among the world’s major cities at 10:35 a.m. (0505 GMT), with a US air quality index reading of 581 — double that of Lahore in neighbouring Pakistan, at 285. Anything above 300 on the US index is classed as hazardous for the whole population, not just sensitive groups.
India’s own Central Pollution Control Board (CPCB) put Delhi’s air quality index at 363 at 10 a.m., in the “very poor” category. The two figures are not directly comparable, because IQAir’s reading is based on concentrations of air pollutants on the US scale while India’s official index uses a different scale and methodology. But both point the same way: the air was already exceptionally bad before the main Diwali celebrations.
Friday’s air quality was the worst pre-Diwali air in eight years, local media said, citing official data. The 24-hour average stood at 382 at 4 p.m. on Friday, and 18 of the city’s 59 monitoring stations recorded readings in the “severe” category on Saturday morning. The government’s Air Quality Early Warning System expected the index to reach the severe band on Saturday itself.
The deterioration is the latest escalation in a smog episode that has gripped the capital all week. On Wednesday the index stood at 377, and authorities had invoked Stage II of the Graded Response Action Plan, the capital’s staged emergency system. On Friday they moved to Stage III, which brings stricter curbs including a halt to construction work and curbs on older vehicles.
India has ordered schools in and around Delhi to offer online classes and encouraged people to work from home ahead of Diwali on Sunday, which is usually marked by the widespread use of firecrackers that further worsen the air. On Saturday the Delhi government said vehicles below BS-VI emission standards registered in other states would be barred from the capital every year between 1 November and 31 January.
Pollution is an annual problem across northern India from the onset of winter, as cold, heavy air traps vehicle emissions, construction dust and smoke from crop-waste burning close to the ground. Diwali threatens to make matters worse: fireworks release fine particles and harmful gases into air already laden with smoke, and last year Delhi woke to a toxic haze the morning after the festival despite a court directive to use less-polluting firecrackers.
The Supreme Court has allowed the manufacture, sale and use of certified green firecrackers in Delhi and neighbouring areas for a limited period, to be set off only between 06:00 and 07:00 and between 20:00 and 22:00 on 7 and 8 November. Enforcement remains a persistent problem: the court has acknowledged that conventional firecrackers have continued to be sold as green alternatives, and has directed police to patrol sales areas and seize illegal stock.
Note: the IQAir figure of 581 is a snapshot from the group’s live ranking at 10:35 a.m. on Saturday and will change through the day; the CPCB figure of 363 is India’s official reading at 10 a.m. The featured image is a file photo of smog over Delhi from an earlier winter, not from today.
Sources: Reuters, “Delhi world’s most polluted major city on eve of Diwali, Swiss group says” (https://www.reuters.com/business/environment/delhi-worlds-most-polluted-major-city-eve-diwali-swiss-group-says-2026-11-07/); The Hindu BusinessLine, “Delhi tops global pollution chart ahead of Diwali; AQI may hit severe on Saturday” (https://www.thehindubusinessline.com/news/national/delhi-tops-global-pollution-chart-ahead-of-diwali-aqi-may-hit-severe-on-saturday/article71678061.ece).
