Image copyright Getty Images Image caption Air quality in Delhi is at hazardous levels after three consecutive days of fine particulate matter (PM2.5) concentrations exceeding permissible limits
Schools in Delhi have been ordered to close from Friday amid the worst air pollution in decades.
The city’s chief minister Arvind Kejriwal said the decision was taken after an advisory from the health ministry.
A London-based expert in air pollution also said the closure was “absolutely necessary”.
Air quality is dropping rapidly in the wake of cooler temperatures and lower wind speeds.
Previous levels of pollution were higher in summer because the city gets most of its warm breezes from the winds on the Indian border, but this time there has been increased congestion in the city.
Image copyright Getty Images Image caption Particulate pollution is a big issue in Delhi
Particulate matter is much lighter than the fine particulate matter known as PM2.5, which can be fatal to people with lung disease.
“From Friday, Delhi will remain under the blanket of air pollution and schools have been instructed to suspend academic activities till 14 January,” AAP party general secretary and Delhi state finance minister Ashutosh told AFP news agency.
Delhi’s air quality has risen from “moderate” levels on Tuesday to “hazardous” on Wednesday, with levels having approached “hazardous” levels in previous days.
The Health Ministry has been running a TV campaign to tell people to be careful with the way they use their daily items, such as lighters.
Image copyright Getty Images Image caption The national capital’s schools have previously closed in times of low air quality
Antonio Vaccino, of the London-based independent climate research firm The Climate Corporation, told AFP the closure was “absolutely necessary”.
“In the next few days, it’s going to get worse. It’s not going to stop. The more these guys are going to use the air outside the more pollution it’s going to get,” he said.
Mr Vaccino also predicted the area would receive about 150mm (5in) of rainfall in January, compared with about 120mm normally received this time of year.
But its rain could be what attracts snow and winds that expel more of the pollutants in the atmosphere.