One possible version:
The environment is becoming worse and worse. There are many kinds of pollution I worry about. The most serious two are water pollution and air pollution, because people can't live healthily with dirty water and polluted air, nor can animals. More and more diseases are caused by polluted air.
I think factories should not pour dirty water into the river directly or produce more waste gas. We'd better go on foot or by like instead of by car, because more cars mean more waste gas. We should make our world more and more beautiful.