China suffers from numerous environmental challenges including problems stemming from water, land, greenhouse gases, and population development. briefly describe the environmental issues being caused by each of these challenges. (site 1)

Considering the fact that china has a large population, they have a substantially high supply and demand. Due to this, China has a large amount of factories that may produce harmful gases that get released into the air. Now, factor in that there are also business from outside of China but have their factories located there, that's more harmful gases. Some careless factories may also dispose of their toxins by dumping them in water. 

exposure to hazardous carcinogens and toxic substances can cause breathing problems, such as copd and various types of cancer. it also increases the risk of heart attacks and strokes and has serious (but no less unattractive) side effects, such as aging, yellow teeth, a terrible smell and damage to the vocal cords.