Air Quality Is Bad Pretty Much Everywhere, New World Pollution Report Finds

The rules of survival are simple: humans can live weeks without food, days without water, but only minutes without air. Air is the most vital resource to human life, and yet what most of the world breathes in every day is dirty.

According to the 2023 World Air Quality Report published on Tuesday by IQAir, a Swiss firm that monitors real-time air quality around the world and has published an annual assessment since 2018, only 10 countries or territories last year had air quality that met the World Health Organization’s standard for clean air.

IQAir used as its primary indicator of each country or territory’s air quality the average concentration of PM2.5, or particulate matter with a diameter of 2.5 micrometers or smaller, measured across cities with publicly-available data. PM2.5 is a harmful component of air pollution that comes from a variety of sources, including emissions from coal and oil burning as well as dust storms and wildfires. The WHO says PM2.5 “can penetrate through the lungs and further enter the body through the blood stream, affecting all major organs” and that exposure to PM2.5 can cause cardiovascular and respiratory health issues, such as strokes or lung cancer. Air pollution is associated with an estimated 7 million premature deaths each year.

WHO guidelines recommend exposure to no more than an annual mean PM2.5 concentration of 5 micrograms per cubic meter (5 µg/m3). Of the 134 countries and territories IQAir was able to assess, only Sweden, Finland, Estonia, Puerto Rico, Australia, New Zealand, Bermuda, Grenada, Iceland, Mauritius, and French Polynesia met that threshold in 2023.

Here are key regional takeaways from IQAir’s 2023 World Air Quality Report.

Asia is the world’s most polluted region

All but one of the 100 cities with the most polluted air in the world are located in Asia, with 83 of them located in India, according to IQAir’s report. Each of these cities had PM2.5 levels that exceeded the WHO’s standard by 10 times or more. The most polluted city, Begusarai, an Indian city of more than half a million residents in the western state of Bihar, had PM2.5 levels of 118.9 µg/m3 last year—or 23 times the WHO standard.

Central and South Asia contain the top four most polluted countries in the world—Bangladesh, Pakistan, India, and Tajikistan—and 31% of the region’s cities reported PM2.5 levels more than 10 times the WHO standard, a proportion vastly exceeding any other region in the report.

IQAir cited several reasons for Asia’s air pollution problem—ranging from the large amount of greenhouse gas emissions from coal-fired power plants and peatbog burning to the El Niño weather phenomenon’s delay of the onset of the rainy season, which would have lessened the impact of PM2.5 levels.

Oceania is the world’s cleanest region

Oceania—comprising Australia, New Zealand, and French Polynesia—remained the region with the cleanest air in 2023, according to IQAir’s report, with each of its countries and territories managing to meet the WHO standard. The region also has the largest proportion, 55%, of reported cities meeting the WHO standard.

Europe is the most improved region

Of the 43 nations monitored in Europe, the annual average PM2.5 levels fell in 36 of them, increased for six, and remained constant for one. Bosnia Herzegovina is still the most polluted country in the region, with an annual average PM2.5 level of 27.5 µg/m3, but even that’s down by 18% from 2022. Croatia showed the most improvement, with its annual average PM2.5 level dropping more than 40% compared to 2022. While 39% of European cities had an annual average PM2.5 level of 10 µg/m3 or lower in 2022, 54% were below that threshold in 2023.

The Americas are the most monitored region

With 3,242 cities analyzed or 40% of the total cities in the report, North America was the most-monitored region, while Latin America and the Caribbean continued a trend of significantly expanding their region’s air-quality monitoring network as new government-operated and non-government-operated monitoring stations popped up in numerous cities and countries, including the Bahamas and Ecuador, that were previously unrepresented in IQAir’s reports.

In North America, Canada surpassed the U.S. for the first time in terms of air pollution since the inception of IQAir’s annual report, due in large part to the massive wildfires that burned from May to October last year. The report said that in May last year, the monthly average air pollution in Alberta skyrocketed almost ninefold compared to the same period in 2022.

The U.S. also saw an uptick in air pollution, climbing from a nationwide average of 8.9 µg/m3 in 2022 to 9.1 in 2023, with the southward-drifting smoke from Canada’s wildfires partly to blame. Columbus, Ohio, was ranked as the most polluted major U.S. city for the second year running with an average PM2.5 level of 13.9 µg/m3, while, Las Vegas, Nev., was ranked the least polluted major U.S. city with an average PM2.5 level of 4.9 µg/m3.

Africa is the least monitored region

The only non-Asian city in the 100 most polluted cities in the world in 2023 was Benoni, South Africa, which had a PM2.5 level of 54.9 µg/m3, or 11 times the WHO standard. But more broadly. Africa faces a major challenge in combating air pollution: its lack of data.

Though the continent’s urban population is rapidly growing, only 24 out of 54 countries, representing 66% of the population, have sufficient air quality data to be included in IQAir’s report.

The country of Chad, which ranked the No. 1 most polluted in the world in IQAir’s 2022 report, was not included because of a lack of publicly available monitoring data.

“Lack of air quality data delays decisive action and perpetuates unnecessary human suffering,” said Frank Hammes, global CEO of IQAir. “Air quality data saves lives. Where air quality is reported, action is taken, and air quality improves.”