The most polluted countries in the world in 2025

In recent years, global warming has finally taken center stage in public debate, gaining the attention and urgency it deserves. But alongside this well-known challenge, there are other emergencies that are still too overlooked and are, in some respects, related to warming. Among these is certainly air pollution, an ongoing issue in many parts of the world, both in cities and major global metropolises.

Every year, alarming reports follow, such as the timely one from IQAir, a Swiss company specializing in analyzing PM2.5 values and other highly dangerous contaminants for human health.

A chilling statistic emerges precisely from IQAir’s World Air Quality 2024 report: Only 17% of global cities meet the World Health Organization (WHO) air quality guidelines.

In the ranking of "virtuous" countries, only seven—including Australia, Estonia, and New Zealand—meet the recommended levels for fine particulate matter.

And then there’s the other side of the coin: countries like Chad, Bangladesh, Pakistan, the Democratic Republic of the Congo, and India record concentrations up to 18 times higher than WHO standards, with devastating effects on public health. And the geographic and social peculiarities of these nations are no coincidence, of course.

Analyzing IQAir data and comparing them with WHO standards, here is the ranking of the most polluted countries in the world.

Particulate Matter Analysis: Health Risks

In its most recent annual report, IQAir paints an alarming picture: 91.3% of countries exceed the WHO recommended limits for fine particulate matter (PM2.5). The data, updated to 2024, comes from over 40,000 monitoring stations spread across 8,954 locations in 138 countries and territories.

While these figures may seem purely statistical, they reveal a concrete reality: PM2.5 particulate matter, as also reported on the Italian Ministry of Health portal, refers to "the set of solid and liquid atmospheric particles suspended in ambient air." It comes primarily from urban and industrial emissions, traffic, domestic combustion, and forest fires, and is so minute that it can penetrate the lungs and bloodstream, damaging vital organs like the heart.

The long-term health effects, therefore, are devastating: chronic exposure to PM2.5 is associated with respiratory and cardiovascular diseases, cancer, neurological effects, and premature deaths, with an estimated toll of approximately seven million premature deaths each year.

As mentioned, according to a shocking analysis, only seven countries in the world comply with the WHO limit of 5 µg/m³ for PM2.5: Australia, Bahamas, Barbados, Estonia, Grenada, Iceland, and New Zealand.

Countries with the worst air pollution: the 2025 ranking

According to the IQAir report, the Central-Southern Asia region is the most at risk. The table below listing the 31 most polluted countries in the world only lists countries with PM2.5 concentrations above 25. That’s 5 times the limit set by WHO guidelines. In the most extreme cases, like Chad, the levels are 18 times the recommended threshold. A huge amount!

The population figures are also telling. We’re not talking millions of people, but billions, representing more than half of our planet’s inhabitants. And the list of nations is long.

Original article published on Money.it Italy. Original title: I Paesi più inquinati al mondo nel 2025. Dov’è l’Italia?