Delhi Tops Global Pollution Ranking Ahead of Diwali

Delhi ranked as the world’s most polluted major city on the morning of November 7, as air quality remained very poor ahead of Diwali. IQAir recorded a US Air Quality Index reading of 581 at 10:35 a.m., placing the Indian capital ahead of Lahore, which registered 285. The readings use a different scale from India’s official index and cannot be compared directly.

The Central Pollution Control Board (CPCB) reported Delhi’s AQI at 363 at 10 a.m., in the very poor category. The CPCB’s 24-hour average for November 6 was 382 at 4 p.m. Under its scale, readings from 301 to 400 are very poor, while 401 to 500 are severe.

An Air Quality Early Warning System forecast that Delhi’s AQI could reach the severe category on November 7. The CPCB reading reported that morning remained in the very poor range. A separate analysis by the Centre for Research on Energy and Clean Air (CREA) said more than 35 of the city’s 59 monitoring stations had average AQI readings above 400 on Friday.

CREA’s analysis found Delhi’s October average concentration of fine particulate matter, or PM2.5, was 69 micrograms per cubic metre, above the national daily standard of 60. The city recorded 21 October days above that...