The 10 cities with the world's worst air

AOL Money Staff
Beijing air pollution
Beijing air pollution

Beijing and New Delhi are tied at the top of a list no city should want to be on: those with the world's worst air quality.

Indeed, one reason - beyond melting glaciers and rising sea levels - that nations are meeting again to try to hammer out some consensus on what to do about earth's deterioriating climate is that the very air we're breathing is dangerous.