In the Punjab region of Pakistan, record-high air pollution levels triggered hundreds of hospitalizations, school closures and stay-at-home orders, as cities and towns remain shrouded in a thick, toxic smog.
On the outskirts of Lahore, the region's biggest city of 13 million residents, the Air Quality Index rose to 1900 on Sunday, according to IQAir, a Swiss company that monitors air quality around the world. It was the worst air quality ever recorded in the city, according to IQAir, and over six times higher than the level classified as "hazardous" by the U.S. Environmental Protection Agency.
Over 900 people, including children and elderly residents, were hospitalized on Tuesday due to the pollution, according to Marriyum Aurangzeb, a senior minister in the Punjab government.
On Wednesday, the Punjab government ordered that all primary and secondary schools shift to remote learning for ten days and instructed half of the workforce to stay home. The government also mandated that residents wear masks.
"This is a critical situation," said Aurangzeb. "I appeal to citizens that for God's sake, don't come out of your houses."
Authorities have created a "smog war room" to tackle the pollution, using strategies like spraying water on the roads, demolishing environmentally harmful brick kilns and banning certain polluting vehicles.
MORE: Why smoke from wildfires could cause a host of symptoms -- even in healthy peopleStudies show the extreme air pollution is caused by the confluence of several factors: farmers in rural areas burn crops during the winter harvest months to clear their fields; brick kilns spew smoke from burning coal near densely populated hubs; and cars using diesel fuel emit fumes as they drive and stall throughout cities.
Aurangzeb blamed "winds from India" for bringing the smog to Pakistan and said she would write to the Indian government to initiate joint efforts to curb the pollution.
"Everybody is coughing and having asthma attacks and allergy attacks," said Sarah Javed, a family physician specializing in respiratory issues at the Vital Care Hospital in Lahore. She saw an influx of patients coming in with sinus, throat, skin, and eye infections due to the smog.
"It reminds all of us of the COVID days," Linda Wali, the director of a primary school in Lahore, told ABC News. "The students do not like to go online and honestly only half the students actually attend these classes."
MORE: What to know about the dangers of wildfire smoke and particulate matterThe U.N. Environment Programme estimates that air pollution leads to 8 million premature deaths every year, calling it the "greatest environmental threat to public health globally." During the wintertime, the cold air traps particulate matter, making the smog denser and longer-lasting.
Doctors recommend that residents use humidifiers, air purifiers and masks whenever possible.
"The smog started very early and at very high levels this year," said Javed. She predicted the problem will only get worse, adding, "Maybe next year the AQI will be over 2,000."