STORY: As a haze of toxic smog smothers India's capital, authorities have announced the closure of primary schools from Saturday.
Delhi's air quality index breached the 'severe' and 'hazardous' categories on Thursday, meaning that the city's 20 million residents are effectively breathing in smoke.
According to data from the Central Pollution Control Board, the AQI exceeded 450 in many places.
A reading over 400 affects healthy people with serious impacts on those with existing diseases.
Before the school closures were announced, some parents were torn about whether their children should be going.
"When we wake up in the morning, we feel that we should not send our children to school. The condition is so bad that when we go to our balcony, we feel difficulty in breathing but it is a matter of their education so we take precautions and send them. We always fear about the effects of pollution on our children's health. This is a matter of concern as with each passing year the situation is getting worse."
"When I step out my eyes become watery, there's a pain in my throat but there is no point is missing out on school because COVID has already caused huge loss to their studies.So, we can teach our children to wear masks (and send them to school)."
Alarmed by the high levels of pollution, India's federal pollution board has banned the entry of diesel trucks carrying non-essential goods into the capital.
Most construction and demolition work has also been stopped to curb dust pollution.
And residents have been told to work from home when they can and reduce the use of coal and firewood.
The world's most polluted capital is blanketed in smog every winter, as cold, heavy air traps construction dust, vehicle emissions and smoke from the burning of crop.