Why is Chang 'an in Xichang always clear?

Does the subject want to ask, "Why is Chang 'an in Xichang always short of water?"? Lack of water and water. Xichang has less rainfall and relatively scarce water resources, so there will be problems such as water shortage, which will lead to poor water quality or unclean water supply. In addition, local water treatment facilities, pipeline systems and other facilities may also have problems, resulting in unstable water quality and difficulty in ensuring water cleanliness.