2. Sweden
We all know that Sweden has a great living standard. Some of the latest researches are showing that Stockholm is one of the best cities for air quality, so it wouldn’t surprise you how this country got to the second place on our list of countries with the cleanest air in the world in 2018. The median concentration of PM2.5 is 6, the death rate is 0.4 per 100,000 capita, and it has a population of 9,910,701.

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