- Of the 10 most polluted cities, nine came from India. These include Ghaziabad, Bulandshahr, Bisrakh Jalalpur, Bhiwadi, Noida, Greater Noida, Kanpur, Locknow and Delhi, which houses India’s capital city.
- The world’s most polluted city was Hotan, which is located in the southwestern region of China’s largest region, Xinjiang. Of the top 10 cities, Hotan was the only one that saw “hazardous” air quality levels, which came in the month of March 2020.
- Indonesia’s most polluted city was South Tangerang in the province of Banten. Thailand’s, on the other hand, was Pai, located in the province of Mae Hong Soon.
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- PM2.5, which are “ambient airborne particulates” that measure up to 2.5 microns, come from fossil fuel-powered vehicles, power generation, industrial activity, agriculture and biomass burning, according to IQAir. The pollutant is associated with health conditions such as asthma, heart disease, lung cancer and strokes.
- IQAir utilized the U.S. Air Quality Index (AQI) to visualize PM2.5 levels that exceed the WHO’s 10 microgram per cubic meter target in 2020. Under this index, exposure to 35.5-55.4 micrograms per cubic meter is considered “unhealthy for sensitive groups,” while exposure to at least 250.5 micrograms per cubic meter is considered “hazardous.”
- Hotan, as the world’s most polluted city in 2020, had an average PM2.5 level of 110.2 micrograms per cubic meter, which qualifies as “unhealthy.” In comparison, the 100th most polluted city, China’s Dezhou, had an average of 50.1 micrograms per cubic meter.
- Lahore, Pakistan’s most polluted city, has seen its residents build their own purifiers and file lawsuits against the government in their despair for solutions. “We can only plead with them to control the pollution,” shopkeeper Ikram Ahmed told AFP. “I am not a literate person, but I have read that Lahore has the worst air quality and then comes India’s Delhi. If it continues like this, we will die.”
- Last year, at least 149 brick kilns in seven upazilas — subdivisions comparable to counties — were found illegally operating in Manikganj, the most polluted city in Bangladesh. The discovery came a year after the High Court ordered the city and its neighbors to shut down all illegal brick kilns within 15 days to reduce air pollution, according to The Independent, Bangladesh.