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The World’s Most and Least Polluted Countries

Updated: Aug 22, 2022

Air pollution has become a global problem. And while many countries are far more polluted than others, there are some that are shining a light on what could be possible for the rest of the world. It's important to note that the world’s most polluted countries are not always those that are the most polluting. Some of the least polluted countries in the world are responsible for the detrimental air quality impact they're having on other places.

How to Measure the World’s Most Polluted Countries

In order to ascertain which are the most polluted countries in the world, the source has to be credible and backed by evidence. For this reason, we decided to use IQAir’s 2021 rich and detailed air quality data, which measures the annual average concentration of PM 2.5 in each country in micrograms divided by cubic metres (µg/m³). Taken from 8,000 data points, the results cover every country in the world as well as some island territories as well.

The results aren’t pleasing, which is to be expected when over 99% of people live in an area with unsafe air.

World’s Most Polluted Countries

It comes as no surprise to find Bangladesh is the world’s most polluted country with 76.9 µg/m³ (only slightly lower the 77.1 µg/m³ measurement of 2020 and 83.3 µg/m³ in 2019). It has led the table in both 2020 and 2019 and although their emissions have decreased, it's not a big enough drop to halt the climate crisis and ensure the health of its citizens. Rounding out the top five most polluted countries in the world are Chad, Pakistan, Tajikistan and India.

It is no surprise that poorer, larger countries are higher up the list than their richer counterparts. There simply isn’t the infrastructure to be quite so pioneering when it comes to air quality in these countries, while their large populations mean that there are more vehicles on the road (many of which are older models and emit more emissions than newer vehicles). Even so, if these countries can move to more eco-friendly energy sources and invest in public transport that emits fewer pollutants, the world’s pollution will quickly dissipate.

The top ten list of the world's most polluted countries as of 2021 is:

  1. Bangladesh – 76.9 µg/m³

  2. Chad – 75.9 µg/m³

  3. Pakistan – 66.8 µg/m³

  4. Tajikistan – 59.4 µg/m³

  5. India – 58.1 µg/m³

  6. Oman – 53.9 µg/m³

  7. Kyrgyzstan – 50.8 µg/m³

  8. Bahrain – 49.8 µg/m³