Delhi overtakes Lahore to become world's most polluted city

Delhi overtook Lahore on Wednesday to become the world's most polluted city in Swiss group IQAir's live rankings. India's pollution control authority said the national capital's 24-hour air quality index (AQI) score had touched 418.

The pollution levels touched the 'severe' category for the first time this season as temperatures and wind speeds dropped, reducing visibility and affecting some flights. At least eight flights were diverted from the city's Indira Gandhi International Airport, news agency ANI reported.

The Central Pollution Control Board defines an AQI reading of 0-50 as "good", and above 401 as "severe", which affects healthy people and seriously impacts those with existing diseases.



Delhi battles smog- a mix of fog and smoke- every winter as cold air traps dust, emissions, and smoke from farm fires.

Pakistan's Punjab province, which shares a border with India and is also battling toxic air, has this month banned outdoor activities, closed schools and ordered some shops, markets, and malls to close early.

The concentration of PM2.5 in Delhi was more than 120 times the World Health Organisation's (WHO) recommended levels on Wednesday morning, IQAir said.


Weather department officials also blamed the smog, which reduced visibility to zero in some places, on high humidity, low wind speed, and the minimum temperature dropping to 17 degrees Celsius from 17.9 C a day before.

Dense fog - defined as that which reduces visibility to 50-200 metres (164-657 ft) - was expected to continue over northwest India for the next 2-3 days, the India Meteorological Department said.

(With agency inputs)