In this article we will evaluate the 20 most unhealthiest countries in the world. You can skip our comprehensive discussion of these countries and go directly to the 5 Most Unhealthiest Countries In the World. The term “unhealthy” can be interpreted in several different ways; a country could be labeled as unhealthy due to a number of reasons such as high pollution, poor healthcare system, insufficient availability of drinking water, child and infant mortality rates, or low life expectancy rates.