Water is an important part of the environment since it supports virtiually all forms of life. As well as being an essential part of diet humans have made use of it for recreation and for economic activity. In recent years various environmental issues have arisen due to this usage. Occurrence Water is widely distributed on Earth in three phases of matter as solid, liquid and gas. Ice is the solid phase. Usage Water pollution *Marine pollution *Ballast water discharge and the environment Water conservation Water conservation is increasingly practised as the demand for water resources increases. *Water wars *Peak water *Water crisis *Irrigation