Opaque and cold smog covered northern India on Monday when low temperatures collided with dangerous levels of air pollution.
In many cities in the region, including New Delhi, the capital, visibility was reduced to 200 meters (656 feet), according to the Department of Meteorology of India.
Late on Sunday, six people, including two children, died when their car slid off the road and crashed into a canal in a suburb of New Delhi, apparently due to poor visibility, the news agency Press reported. Trust of India
"Preliminary investigations indicate that the accident took place due to low visibility due to fog." said local police officer Akhilesh Pradhan.
Analysis: New Delhi smog threatens the health of Indian residents
With temperatures falling to a degree Celsius (34 degrees Fahrenheit) in New Delhi, street vendors, author car drivers and homeless people wrapped themselves in sweaters and hooded blankets, and warmed their hands on small fires.
The city had to register its coldest December day since 1901.
The notorious winter air pollution in New Delhi worsened the air quality index to a level 10 times higher than what the World Health Organization considers safe.
The pollution has cooled the air, mixing with moisture in low wind conditions to create low-altitude clouds that extend from eastern Pakistan to the eastern state of Bihar, said Rajendra Kumar Jenamani, a scientist at the Department of Meteorology of India .
The cold and fog were expected to continue on New Year's Day, according to government weather data.
Delayed, canceled flights
Conditions interrupted hundreds of flights on Monday.
At least 500 flights from Delhi's Indira Gandhi International Airport were delayed due to dense fog on Monday and at least eight flights were canceled, a spokesman for the airport authority said.
In the northeastern state of Assam, zoo authorities placed heaters in enclosures to protect tigers from reinforcement conditions.
"The animals are not used to this and we are taking special measures to keep the animals, particularly the old ones, hot," Texas Mariswamy of the Assam State Zoo told AFP news agency.