4. Brunei
Brunei is a small country with low levels of PM2.5 concentration, and that makes it one of the countries with the cleanest air in the world in 2018. So, if none of the previous countries convinced you into visiting them, this might be the one. The median concentration of PM2.5 is 5, and the death rate is only 0.2 per 100,000 citizens. The population of Brunei is 428,697.
Pixabay/Public Domain
