Dirtiest Cities in the World

Mexico City, Mexico:

Mexico City, the capital of Mexico, and the capital of North American air pollution, estimates unhealthy ozone emissions nearly 85 percent of the year. Mexico's geographical location is in the center of a volcanic crater and surrounded by mountains and this only serves to lock in the air pollution, causing smog to sit above the city. The industrial and automobile emissions for air quality are so bad that city ozone levels fail to meet WHO standards.

Addis Ababa, Ethiopia:

Addis Ababa, the capital of Ethiopia is also one among the dirtiest cities in the world. It faces one of the worst sanitation problems on both the continent of Africa as well as in the world. The lack of adequate sanitation programs has resulted in infant mortality, low life expectancy and the transmission of water-borne diseases.