The water is dirty.

Water is very important for life on Earth. It is in our oceans, seas, rivers and lakes. There is a lot of water in our planet and at the same time there is littel water in it. This is because very little water is good for drinking. Sometimes people cannot swim even in the sea because the sea and the seaside are not clean. This is because of the modern plants and factories, which are sent in our water a lot of bad things. For example, Lake Baikal is the deepest freshwater lake on Earth. It is 1741 metres deep. The lake is very beautiful but it is in great danger, because of the factories. They must to protect water in our planet!

Я придумывала сама и немного брала из интернета.

Надеюсь, помогла.