What is the most serious pollution in China?

The air pollution is the most serious pollution in China

　　I think air pollution is the most serious pollution in China. We human being cannot live without air. Once the air is polluted, our health is threatened. There are two main atmospheric pollution sources: one is natural, and another is man-made. We can do nothing to control the former, but we can control the latter. Burning coal provides 75 percent of the energy in China. The waste air emitted from the coal burning contains a lot of sulfur elements mostly existing in the sulfur dioxide gas, which will turn into acid rain after a series of chemical reactions and changes. The using of agriculture poisons is another origin of the man-made air pollution. So we should use as less poisons in agriculture as we can and try to use some biological method to kill the harmful insects.
　　In conclusion, the main causes of the pollution of China are air, water, land and noises. Any kind of pollution has a bad impact on our d