Pollution has been a serious problem for a certain time around the world.There are many causes for it.Transportation is the main factor of pollution.When the waste gas from cars is released,the air is polluted.People breathing in the polluted air can develop respiratory disease.Another factor is that people throw their garbage everywhere.All kinds of garbage not only spoil the splendid environment,but also cause environmental pollution.What's more,industrial pollution also deserves our attention.Wastewater from factories is poured into rivers and this causes water pollution.As a consequence,the greenhouse effect becomes a problem which needs our immediate caution and how to solve is urgent all over the world.At present,some measures have been taken to prevernt.For example,people classify the garbage and some is recycled after being collected.People are also encouraged to use paper products instead of plastic products because we know that our living condition will be worse if we keep ignoring this problem.And I believe we can prevent pollution if everyone makes the efforts.