The Pakistani city of Lahore experienced its worst air quality levels in 2022, according to an assessment by IQAir, a Swiss air quality technology company. China’s Hotan took second place and India’s Bhiwadi won the bronze medal. (In 2021, they were the three most polluted cities in India.) In last year’s air pollution rankings, Delhi ranked first among the world’s capitals, followed by the capital of Bangladesh, Dhaka, and the capital of Chad, N’Djamena. These cities averaged more than 90 micrograms of PM 2.5 per cubic meter over the course of a year, or nearly 20 times the recommended level. Kazincbarcika turned out to be the most polluted Hungarian city in this group, but the amount of PM2.5 did not reach four times the recommended level. (PM 2.5 refers to dust particles smaller than 2.5 micrometers.)
The Swiss company used data from more than thirty thousand air quality measuring devices in 7,323 cities in 131 countries and regions. Analysts looked at the World Health Organization level for PM2.5 particles (from) It was above or below the limit that was reduced from ten to five micrograms per cubic meter in 2021. (Air pollution is estimated to cause about seven million premature deaths each year.) Based on Swiss measurements, the six countries with the cleanest air are Australia, Estonia, Finland, Grenada, Iceland and New Zealand.
Although the measurements reveal some air pollution hotspots, it is impossible to pinpoint which cities actually have the worst air. The quality of the sensors used varies, and many African countries are not included in the list because they do not report the data. By the way, there are many reasons why some cities have more PM 2.5 in their air than others. One factor is geography. Hotan is located near the Takla Makan Desert, where dust storms are common. N’Djamena was built near another desert, the Sahara. Mountains can affect air quality by making it difficult to extract pollutant-rich air from settlements. Delhi, Lahore, Dhaka and many other cities with unhealthy air are located south of the Himalayas.
“Anything you touch in Delhi will be dusty, even if you clean it every day,” Umesh Kulshrestha, dean of the School of Environmental Sciences at Jawaharlal Nehru University in New Delhi, told the Live Science portal. Rare rainfall outside the monsoon season helps dust accumulate, and small particles come not only from remote deserts but also from unpaved roads and construction sites in cities.
A large proportion of the city’s PM 2.5 pollution comes from vehicles, power plants and industrial sources. In an article published in the journal Aerosol and Air Quality Research, Umesh Kulshrestha found that during the pandemic lockdowns in early 2020, air pollution in Delhi fell by 41 percent, thanks to lower vehicle and industrial emissions.
