求下面文章每段的大意 用一句话英语来概括

water and air clean . That means keeping the land . They stop the people from burning coal in houses and factories in the city , and from blowing dirty smoke into the air .
The pollution of SO2 is now the most dangerous problem of air pollution . We must take care of it . It is caused by heavy traffic . It’s bad to all living things in the world , but it is not only one kind of pollution. Water pollution kills our fish and pollutes our drinking water , there will be less air pollution .
The earth is our home . It is sure that if there are fewer people driving . Noise pollution makes us become angry more easily .
Many countries are making rules to fight pollution Man has been polluting the earth . The more people , the more pollution. Many years ago, the problem was not so serious because there were not so many people. When the land was used up or the river was dirty in a place , men moved to another place. But this is no longer true. Man is now slowly polluting the whole world .
Air pollution is still the most serious

1 The pollution problem we now face has a lot to do with population growth.
2 There are all kinds of pollution that affetcs our life.
3 The air pollution is caused by a number of reasons.
4 It is important for us to do everything we can to keep the earth clean.

me