Classes have resumed in schools and colleges that were shut in the Indian capital due to the toxic air pollution even as the air quality remains in the "very poor" category, officials said.

However, the ban on construction activities will stay until further orders. Goods trucks have been barred from entering the city until Dec. 7, Delhi Environment Minister Gopal Rai said.

Schools that shifted to online classes starting Nov. 15 have resumed in-person classes. But parents worry that their children are being exposed to polluted air.

Earlier, the government and private firms in New Delhi, Haryana, Rajasthan and Uttar Pradesh states have been advised to allow at least 50% of staff to work from home.

The air quality index in Delhi has been oscillating between the "very poor," "severe" or "hazardous" levels since early November. But officials said the situation may improve later on Monday if winds disperse the pollutants.

Fine particulate matter (PM2.5) levels hit 380 in the city, more than five times the limit deemed safe by the World Health Organization (WHO).

Government offices also reopened, with employees working from home for the past two weeks now reporting to their office.

The Supreme Court asked Delhi and authorities in surrounding states to file compliance reports on recent orders by a federal air quality management panel on curbing pollution, legal news portal Live Law reported.

Delhi, with 25 million inhabitants, has been ranked among the world's most polluted cities in recent years. Seasonal crop stubble burning by farmers, along with climatic factors like lack of surface winds, addition in emissions from heavy traffic and factories, and the burning of garbage and fuel spike air pollution in the city every October and November.

Auto emissions contribute nearly 25% of the city's pollution during the winter, according to the government.

Several studies have estimated that more than 1 million Indians die each year from air pollution-related diseases. In 2020, 13 of the world's 15 cities with the most polluted air are in India, according to the Swiss air quality monitoring company IQAir.