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Why Some Countries Are Impacted By Air Pollution More Than Others

NEW DELHI, INDIA - OCTOBER 29: A commuter walks near India Gate amid heavy smog pollution on October 29, 2025 in New Delhi, India. Delhi is once again blanketed by hazardous smog following the Diwali festival, as pollution levels spike to the "very poor" and "severe" categories, with air quality indexes far exceeding safe limits. The crisis, which is driven by firecracker use, emissions, and seasonal crop residue burning has prompted emergency measures like cloud seeding. (Photo by Ritesh Shukla/Getty Images)

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Often when scientists talk about air pollution, they talk about the inequalities at local and regional level, and how some communities are more impacted than others.

But the same is also true at a national and international level, with some countries around the world facing higher levels of exposure.

The research from Lutz Sager, an assistant professor from the ESSEC Business School, argues that the largest disparities around fine particulate matter pollution, sometimes known as PM2.5, are not mainly within countries, but between them.

Sager said while research shows a growing inequality between countries between 2000 and 2020, with just a handful of countries facing the highest levels of exposure.

He told me despite decreasing PM2.5 pollution levels in Europe and North America over this time period, other parts of the world, particularly Asia and Africa, facing increasing levels.

The report highlights how the global Gini index for PM2.5 air pollution exposure, which measures how unequally fine particulate matter is distributed among the world's population, has risen from 0.30 to 0.35 by 2020.

He said this increase makes pollution exposure inequality greater than income inequality in many countries.

And the study also focuses on what Sager calls the ‘choking billion’, who are the 1 billion people who face the highest average daily levels of particulate pollution on the planet, almost 12 times higher than the 5 microgram limit proposed by the World Health Organisation.

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Sager said almost half (479 million) of those 1 billion people affected live in India, while 184 million are in China, 128 million live in Bangladesh, and 85 million live in Pakistan.

“The data in the report shows there is excessive inequality worldwide,” Sager told me.

“We sometimes focus on inequality within individual countries, and it's true there is inequality within countries, but compared to the inequality between France and India, it’s on a very different level.”

The report also highlights how the inequalities in health burdens associated with particle pollution is even more unequal than the actual exposure itself.

“If we have higher levels of pollution in places where people might be more vulnerable, this can multiply, and so the actual health burden seems to be even more unequal than the pollution exposure,” he said.

Dr. Christa Hasenkopf, a senior fellow at Clean Air Fund, said the growing inequality across countries the study identifies largely tracks with the global picture of how resources are devoted to addressing air pollution, in a statement.

Dr. Hasenkopf added the Clean Air Fund’s own research shows air pollution receives less than 0.1% of global philanthropy, which she said was a “tiny sum” compared to the harm of one of the world's largest public health problems.

She said many of the most polluted regions, including several where the study finds the most unequal impacts, receive a tiny portion of those clean air funds.

“Africa, for example, attracts just 1% of global clean air funding,” said Dr. Hasenkopf.

“Meanwhile, North America, with its relatively cleaner air, receives the lion's share. This continent-level inequality leaves entire countries without even the most basic clean air infrastructure, like a single air quality monitor.

“The good news is even small investments in infrastructure could have outsized returns for the 'choking billion’ the study calls out.," she added.

"Less than $100,000 a year can provide a country's first reference-grade air monitor and catalyse national clean air progress.”

Glory Dolphin Hammes, the chief executive of IQAir North America, said there is no single reason why some countries are more impacted by air pollution than others, in a statement.

She added it is the result of a number of factors, including energy production, industrial activity, transportation, urbanization, geography, climate, and public policy.

“Pollution does not respect borders, and emissions from one country can travel hundreds or even thousands of miles, affecting air quality elsewhere,” she said.

“Ultimately, air pollution is not inevitable, but reducing it requires sustained investment in cleaner energy, stronger policies, effective emissions controls, and reliable air quality monitoring.”