Millions of people in India's capital started the week Monday choking through "eye-burning" smog, with schools closed, cars taken off the road and construction halted.
A poisonous haze envelops New Delhi every winter, caused by vehicle fumes, industrial emissions and smoke from agricultural burning in neighboring states.
But the current crisis has turned into the worst in three years, and New Delhi Chief Minister Arvind Kejriwal called for a range of measures to fight what he described as "unbearable pollution".
"There is smoke everywhere and people, including youngsters, kids, elderly are finding it difficult to breathe," Kejriwal said in a Twitter video on Sunday.
"Eyes are burning. Pollution is that bad."
Kejriwal's government has ordered half the city's private cars to be taken off the road, based on an odd-even registration plate system.
Schools, which were closed on Friday last week, remained shut on Monday, and city-wide construction was halted until Tuesday in Delhi and surrounding areas.
Kejriwal said authorities were also distributing face masks to schoolchildren.
Other parts of the country have also been choked by smog, the government's Central Pollution Control Board said Sunday.
Authorities brought a van with an air purifier to the Taj Mahal, the country's top tourist site 250 kilometers (150 miles) south of Delhi, with fears the pollution was damaging the 17th-century marble mausoleum, the Press Trust of India reported. (AFP)