MNN Galleries

The 10 worst pollution problems in the world

By: chief on Oct. 16, 2009, 11:21 p.m.
A dead fish on a polluted, muddy shore

Photo: iStockphoto

8 of 12

Untreated sewage

In many poor areas of the world, human and household waste gets discarded into local waterways where it poses a major health threat. Untreated sewage hosts a number of waterborne diseases, including cholera, typhoid and dysentery.