Schools in India's capital of 20 million people have been asked to shut down. Here's why

A filthy smog forms over the Indian capital every winter, causing a surge in respiratory illnesses among in New Delhi.

A dense blanket of smog covers central Delhi amid deteriorating air quality levels on 4 November 2022 in New Delhi, India. Residents woke up to smog-filled surroundings on Friday as AQI continued to show alarming numbers. Source: AAP / Getty Images

Key Points

• Delhi chief minister Arvind Kejriwal said primary schools would be closed until "the pollution situation improves".
• A Lancet study in 2020 attributed 1.67 million deaths to air pollution in India during the previous year, including almost 17,500 in the capital.

Authorities in New Delhi ordered primary schools to shut from Saturday and told schools to stop outdoor activities for older children as air in the world's most polluted capital had become a severe health risk.

Smoke from farmers burning crop stubble, vehicle exhaust, and factory emissions combine every winter to blanket the megacity of 20 million people in a deadly grey haze.

The city is engulfed in heavy smog near Rajpath, in New Delhi, India, on 3 November 2022. Source: AAP / EPA

On Friday, levels of the most dangerous PM2.5 particles — so tiny they can enter the bloodstream — were almost 25 times the daily maximum recommended by the World Health Organization, according to monitoring firm IQAir.

Delhi chief minister Arvind Kejriwal, under fire from residents and political opponents for failing to address the crisis, said primary schools would be closed from Saturday until "the pollution situation improves".

"No child should suffer in any way," Mr Kejriwal told reporters.

Delhi is frequently ranked as one of the world's most polluted cities. On Friday, it again topped IQAir's list of major cities with the worst air quality.

A Lancet study in 2020 attributed 1.67 million deaths to air pollution in India during the previous year, including almost 17,500 in the capital.

Authorities regularly announce different plans to reduce pollution, for example, by halting construction work, but to little effect.

Tens of thousands of farmers across north India set fire to their fields at the start of every winter to clear crop stubble from recently harvested rice paddies.

The practice is one of the key drivers of Delhi's annual smog problem and persists despite efforts to persuade farmers to use different clearing methods.

Farm fire smoke accounted for a third of Delhi's air pollution on Thursday, according to India's air quality monitoring agency.

The problem is also a political flashpoint — with Delhi and the northern state of Punjab governed by the Aam Aadmi Party (AAP), a rival to Prime Minister Narendra Modi's Bharatiya Janata Party.

Air pollution in India's capital Delhi and its surrounding areas continues to be a problem. The problem burgeons mainly in winter months when air density comparatively decreases. Source: AAP / Getty

But Mr Kejriwal called for an end to "blame games and finger-pointing" over responsibility for tackling the smog after India's environment minister lambasted the AAP for presiding over an increase in farm fires.

"It won't help in finding solutions. We can blame them, and they can blame us, but that would lead to nothing," he said.

"Farmers need solutions," he added.

"The day they get a solution, they will stop burning the stubble."