Thick blanket of smog prevailed in Delhi on Monday as the air quality deteriorated sharply overnight in the capital, triggering warnings that even healthy people were at risk of respiratory problems.
Angered with the rising pollution, a large number of protesters wearing masks took to the streets on Sunday of as the city remained blanketed under a cloud of toxic smoke that has lingered for a week and sparked anger at the government's slow response.
The Arvind Kejriwal government has ordered thousands of schools to remain shut for three days till the air quality improves in the national capital. The thick layer of smog also led to the cancellation of Ranji Trophy match.
Delhi residents have been advised to stay inside as the air pollution crisis in the city and the surrounding metropolitan region - deemed an "emergency situation" by the environment minister on Saturday - stretched into its seventh day.
Patients with breathing problems inundated hospitals and doctor's clinics, and residents waited in line to buy pricey face masks - which often sold out.
"We have never seen something like this. This time things are really bad," said P.S. Walia, 44, a father of two who was at a protest on Sunday.
Experts said low winds, holiday fireworks residue and crop-burning in neighboring states contributed to the haze, which reduced visibility at the airport to a 17-year low last week.
Air-quality data from the U.S. Embassy's air monitor - which measures the particulate pollutant known as PM 2.5 - averaged 640 this week, more than six times the level deemed acceptable by the Environmental Protection Agency.
The US embassy in Delhi said its air pollution index late on Sunday had breached the "hazardous" upper limit level of 500, at which it stops measuring levels of particulate matter, reported BBC.
Gufran Beig, chief scientist at India's state-run System of Air Quality Weather Forecasting and Research (Safar), told AFP news agency, "Almost 60-70% of the smoke came from the firecrackers."
“The levels we’re seeing are really alarming. They are clearly in the severe category,” Anumita Roychowdhury, the executive director of the Centre for Science and Environment, a Delhi-based thinktank, was quoted as saying The Guardian.
“Delhi’s air remains so polluted throughout the year that it doesn’t really have room for additional pollution during Diwali,'' she added.
The Wall Street Journal too reported that air pollution in New Delhi has reached dangerous levels post Diwali celebrations.
New Delhi ranks among the world's most polluted cities, with air quality usually worsening at this time of year, when smoke from firecrackers celebrating Diwali - the festival of lights - and burning of crops in nearby states envelops the city of 16 million.