北京沙尘暴的原因

The cause of sandstorm in Beijing
Since Yuan Dynasty，Beijing Have Had Records of sandstorm which mainly Happens in spring. So far, there is no evidence that if Beijing sandstorm is strengthening or weakening. Sand and dust of Beijing sandstorm stems from both inner and outside Beijing region.Outside cause of Beijing sandstorm is global climatic change, inner cause is overweight of population pressure and non-harmonious population-land relations. To prevent Beijing sandstorm, China should take vigorous action to look for international co-operation so as to reduce discharge of hothouse gas and accept international aid, to issue a series of relative policies, also Beijing should work out concrete active plans.
http://us.tom.com/english/257.htm
这个网页的资料可以作为补充参考。

翻译？
the reasons that cause the sandstorm in Beijing