Dense, noxious smog enveloped the Indian capital and surrounding area Sunday, causing residents to suffer from burning eyes, sore throats, and shortness of breath.
Pollution levels in New Delhi hit a three-year high, forcing 37 flights to be diverted from the city's international airport due to low visibility.
The Central Pollution Control Board (CPCB) said the capital's average air quality index (AQI) hit 494 at 4 p.m. local time on Sunday, the highest since November 6, 2016, when it was 497.
Air quality is considered good when the AQI is below 50 and satisfactory when it's under 100.
AQI between 301 and 500 is considered "hazardous" for all population groups. It is not measured past 500.
Delhi's Chief Minister Arvind Kejriwal tweeted that the pollution level was "unbearable" and urged the central government to intervene.
New Delhi, ranked the world's most polluted city by Greenpeace and AirVisual, routinely gets more polluted at this time of the year. The air quality gets noticeably worse as winter approaches and farmers clear their fields by burning scrub. The pollution is also made worse by smoke from firecrackers lit all across the region to celebrate Diwali, Hinduism's biggest holiday.
The local governments have ordered all schools and colleges to remain closed at least until Tuesday. Drivers in the city of more than 18 million people and 8.8 million registered motor vehicles have been asked to follow the odd-even road rationing plan until November 15. Under the plan, cars will only only drive on odd and even dates that correspond with the last digit of the license plate number.
