People cover their faces as they walk in heavy dust and smog in New Delhi. (Harish Tyagi/European Pressphoto Agency)

Mask-wearing protesters took to the streets of the Indian capital Sunday 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.

Thousands of schools have been shuttered, cricket matches canceled and residents warned to stay inside as the air pollution crisis in New Delhi and the surrounding metropolitan region — deemed an “emergency situation” by the environment minister Saturday — stretched into its seventh day.

Patients with breathing problems inundated hospitals and 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 Sunday. He has shuttered his house, stopped taking morning walks and kept his kids indoors this past week to protect them from the stinging air.

Protesters wearing protective masks take part in a rally urging immediate action to curb air pollution. (Sajjad Hussain/AFP/Getty Images)

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.

On Sunday, Delhi’s chief minister, Arvind Kejriwal, said the city would undertake emergency measures to address the “need of the hour,” including banning construction activity for five days, limiting diesel-generator use, water-treating dusty roads and temporarily closing a coal-fired power plant. The city’s schools will remain shut for three days, he said.

Environmental experts applauded the move but say the city — the 11th-most-polluted in the world, according to the World Health Organization — needs far more stringent long-term solutions. Last week, the country’s environmental court had chided both the central and state governments for “shifting blame” and not taking action to address the problem.

“Emergency measures are an absolute necessity right now because the levels we are seeing are too horrendous,” said Anumita Roychowdhury, head of the Center for Science and Environment’s air pollution and clean transportation program. But longer-term fixes — expanding public transport, permanently closing aging coal-fired plants and controlling waste-burning — are necessary, she said.

Kejriwal said Saturday that farmers in the neighboring states of Punjab and Haryana had illegally burned 16 to 20 million tons of crop waste in the past month, turning the capital into a “gas chamber.” The states’ environment ministers are set to meet Monday to come up with a plan to address the problem.

“So much is caused by the burning of crops. The government has to do something,” Satish Mittal, a roadside tea-stall owner, said Sunday.

Kejriwal’s government has made attempts to control pollution, including two trials of a controversial plan this year to limit car use by odd- or even-number license plates, a program that reduced traffic but did not have the dramatic effect on air quality some had hoped for.

Hundreds gathered for a protest walk in the tech suburb of Gurgaon on Saturday and at a rally near Parliament in New Delhi on Sunday. There, the masked protesters were joined by schoolchildren with hand-lettered signs that said “Be the solution to the pollution” and “Help Delhi Breathe.”

One of the organizers, Shivani Gupta, 41, a jewelry designer, said her son — who has become severely asthmatic — was hospitalized three times last year because of pollution. The family has even taken to wearing protective masks inside their house.

“My husband is sick, and my child is sick,” she said. “This is not how we can live our lives.”

Swati Gupta contributed to this report.

CORRECTION: This article has been updated to include the correct figures for the amount of crop waste burned near New Delhi in the previous month.