On Tuesday, Delhi became a gas chamber as air quality touched 999, the highest the machines can read.
This is the worst air pollution day recorded in Delhi for the season so far.
Chief Minister Arvind Kejriwal said it has turned Delhi into a 'gas chamber' and blamed the burning of stubble in neighbouring states for Delhi's poor air condition.
The CM Tweeted: "Delhi govt wrote letters to adjoining states in Aug urging them to take steps to check crop burning"
Arvind Kejriwal also tweeted that he has asked Education minister Manish Sisodia to order schools to remain closed for the next few days considering the high level of pollution in the state, in reply to which, the Education Minister said "Have called a meeting at 5:30 pm to discuss the deteriorating air condition of the capital.
The Indian Medical Association has also written to the CM to cancel the Airtel Delhi Half Marathon scheduled to be on November 19 due to 'high level of air pollution.'
Delhi Half Marathon title sponsor Airtel on Monday hinted that it may have to stop associating with the event from next year if the "authorities" refuse to address the issue of air pollution in the Capital.
"Air pollution poses serious health risks and it is important that these concerns are addressed urgently and appropriately by the authorities for Airtel to continue associating with the event next year and beyond," the telecom major said in a statement.
Dense smog hampered visibility at the Delhi airport this morning, affecting flight operations and leading to delays by up to two hours as only one of the three runways could be used.
Air quality in Delhi began plummeting on the intervening night of Monday and Tuesday as moisture combined with pollutants shrouded the city in a thick cover of haze.
A bench headed by NGT chairperson Justice Swatanter Kumar lambasted the state governments for not being prepared in advance to tackle the emergency situation.
Visibility was down to 200 metre at 8.30 A.M, but the India Meteorological Department (IMD) said it was due to fog and not smog, adding that temperatures had dropped to 17 degrees Celsius early on Tuesday.
The Central Pollution Control Board (CPCB) said high moisture level in the air has trapped emissions from local sources and hanging low over the city in the absence of wind.
"Total calm conditions, marked by the complete absence of wind has led to the situation. The moisture has trapped emissions from ground-level sources," Dipankar Saha, CPCB's air lab chief, said.
Saha said air from neighbouring Punjab and Haryana, where paddy stubble burning is in full swing, is not entering the city as of now. When it starts, the situation is expected to deteriorate further.
The CPCB recorded 'very poor' air quality in the national capital. Neighbouring Noida and Ghaziabad, however, recorded 'severe'air quality.
The real-time pollution monitors displayed alarmingly high concentration of PM2.5 and PM10, which are ultrafine particulates having the ability to enter the respiratory system and subsequently the bloodstream of humans and animals, causing harm.
A 'very poor' AQI comes with the warning that people may develop respiratory illness on prolonged exposure while exposure to 'severe' air affects healthy people and seriously impacts those with existing respiratory or cardiovascular diseases.
(With inputs from agencies)