Question: What is the most polluted country?

Michael Gillin answered on 24 Mar 2026:

Depending on your definition of “most polluted” and the current rankings, many people would consider Pakistan, Tajikistan, Chad, Bangladesh, India, Nepal, and Qatar as being among the most polluted.

These are ranked by the concentration of particulate matter in the air around those countries.

Alternatively, if you consider water pollution, the Central African Republic has extremely polluted water.