Dozens of flights have been delayed, diverted or cancelled at Indira Gandhi International Airport after New Delhi experienced its worst air pollution levels in three years.
Authorities in the world's most polluted capital city had already declared a public health emergency and ordered the closure of schools as air quality deteriorated.
Passengers faced delays and disruption at the airport yesterday as more than 30 flights were diverted due to poor visibility that could impede take-off or landing.
Flights to and from New Delhi to the UAE appear to still be running to schedule.
Vistara airlines took to Twitter to alert passengers to the disruption, which is still ongoing.
The Air Quality Index, measuring levels of PM 2.5, tiny particulate matter in the air, reached more than 900, way over the 500-level that qualifies as "severe-plus". This made conditions difficult for aircraft attempting to take off or land in New Delhi.
Spice Jet apologised to passengers for the disruption to flights caused by poor visibility.
Aside from the air travel chaos, the high levels of toxicity affected the 40 million people living in the capital region.
Roads looked deserted as large numbers of people stayed home, rather than expose themselves to the noxious atmosphere outside.
"Pollution has reached unbearable levels across north India," Arvind Kejriwal, Delhi's chief minister, said in a message on Twitter.
Country under smog grip
The government environment monitoring agency SAFAR warned that no relief was expected for the next one to two days, as humidity resulting from unexpected light rains overnight had exacerbated pollution, already driven higher by farmers' seasonal crop stubble burning in the surrounding states.
Priyanka Chopra posted a shot of her sporting a face mask in the Indian capital on her Instagram. The actress, who is married to musician Nick Jonas, is in New Delhi shooting for her upcoming Netflix project White Tiger.
Chopra asked people to pray for the homeless; the estimated 150,000 people living on the streets of New Delhi have no escape from the smog.
"Wind speed is picking up and it could take 24 to 48 hours before the pollution level reduces to a level of around 500," Mahesh Palawat, vice president of Skymet, a private weather forecasting agency, said.
Anything above 400 on the AQI poses a risk for people with respiratory illness and can also affect even those with healthy lungs.
At the Yamuna River, one of the country's most sacred waterways, toxic-laced foam floated on the river surface. Devotees braved the hazardous water to wade knee-deep into the river to offer prayers for Chhath Puja, an ancient Hindu Vedic festival.
Doctors were reporting a spike in patients with respiratory-related issues, according to Sachin Taparia, head of Local Circles, a Delhi-based private consultancy that conducts surveys on government policies and programmes.
"Delhi has turned into a gas chamber as the pollution levels hit the ‘severe+’ category," Taparia said.
Authorities in Delhi on Friday declared a public health emergency and closed schools and all construction activity.
This annual peak in air pollution in Delhi occurs thanks to a mix of smoke from firecrackers used in Diwali celebrations, the burning of crops by farmers in neighbouring regions and a dip in temperature as India rolls towards winter.