carbon monoxide: because it can not be cleared naturally
China
Asia does.
Both are as bad as each other but in a completely different way. 'Sound pollution' is called 'noise pollution'.
Chemicals such as pesticides cause water pollution from storm runoff.
China is the country with the highest air pollution with 21.5% of the global total.
your moma niggha
co2
It is generally believed that the worst oil pollution in central Asia is in the Caspian Sea. The amount of oil spills in the region is quite alarming.
The city of Los Angeles is generally considered to have America's worst air pollution problem. Most of California's metro areas have bad air pollution.
El Paso!
The cities that have the worst air pollution is Pittsburgh and Los Angeles
The EPA recently conducted a survey in which San Bernardino, and its county, has the worst air pollution rating of any city\county in the U.S. I'm sorry, I don't have the numbers, though.