Authorities in India closed schools indefinitely and shut down some coal-burning power plants on Wednesday to reduce air pollution in the smog-shrouded capital and neighbouring states, as the country considered a lockdown in New Delhi.

The dirty-air crisis in the city of more than 20 million people has underscored India’s heavy dependence on coal, which accounts for 70% of the country’s power.

The New Delhi state government said it was open to the idea of a weekend lockdown to reduce vehicle traffic and potentially other air-polluting activities in the city, and it was awaiting the go-ahead from India’s Supreme Court. A decision could be made from November 24.

It is not clear how extensive the lockdown would be. Authorities are discussing whether to allow industries to continue operating.

Some experts said a lockdown would achieve very little in controlling pollution and would instead cause disruptions in the economy and harm the livelihoods of millions of people.

“This is not the solution that we are looking for, because this is hugely disruptive. And we also have to keep in mind that the economy is already under pressure, poor people are at risk,” Anumita Roychowdhury, executive director at the Centre for Science and Environment, a research and advocacy organisation in New Delhi, said.

Soaring pollution levels in the capital prompted a federal environment ministry panel to issue strict guidelines on Tuesday night to stem the pollution and show residents that the government was taking action against a crisis that has plagued the city for years.

Besides closing schools and shutting down some power plants, the Commission for Air Quality Management ordered a halt to construction until November 21 and banned trucks carrying non-essential goods. The panel also directed the affected states to encourage working from home for half of the employees in all private offices.

The importance of coal to India was underlined days ago at the world climate talks in Glasgow, where almost 200 nations accepted a compromise deal to fight global warming. It contained a last-minute change sought by India that watered down crucial language about coal.

The agreement as amended would “phase down” rather than “phase out” coal power, the biggest source of greenhouse gas emissions.

Levels of dangerous particles in New Delhi’s air on Wednesday were as high as seven times the safe level, climbing above 300 micrograms per cubic metre in some parts of the city. The World Health Organisation designates the safe level as 25.

Forecasters warned that air quality would worsen before the arrival of cold winds next week that would blow the smog away.

Earlier this month, air pollution reached the “severe” level in the capital, and residents faced bouts of heavy pollution over several days. This prompted the Supreme Court last week to order state and federal governments to take “imminent and emergency” action. New Delhi authorities responded by proposing a lockdown and closing schools for a week.

Among the many Indian cities suffering air pollution, New Delhi tops the list every year.

Vehicle emissions contribute nearly 25% to the city’s pollution in the winter, according to the federal government. The crisis deepens in the cold-weather months when the burning of crop residue in neighbouring states coincides with lower temperatures that trap smoke. This smoke then travels to New Delhi.

Emissions from industries with no pollution-control technology, smoke from firecrackers linked to festivals, and construction dust also sharply increase in winter months.

Several studies have estimated that more than a million Indians die each year because of air pollution-related diseases.

The capital has often experimented with limiting the number of cars on the road, using large anti-smog guns and halting construction. But the steps have had little effect.

Experts say such emergency measures are not helpful in the long run.

“These are done only to ensure that you don’t worsen the situation, that you shave off the peak. But it is not a silver bullet that is going to just clean the air immediately,” Ms Roychowdhury said.