Among all the natural factors that maintain human survival, economic construction and social development, the importance of water goes without saying. However, with the acceleration of industrialization and urbanization, the world is facing the challenges of water shortage and serious pollution. China is particularly serious. It is one of the 13 water shortage countries in the world. About half of the country's more than 600 cities are currently short of water. The deterioration of water pollution makes the water shortage worse.

China's rivers and lakes are generally polluted, and 75% of the country's lakes are eutrophic to varying degrees; 90% of urban waters are seriously polluted, and 60% - 70% of the total water shortage in southern cities is caused by water pollution; According to the survey of groundwater in 118 large and medium-sized cities in China, 115 cities have been polluted, of which about 40% are seriously polluted. Water pollution reduces the use function of water bodies, exacerbates the shortage of water resources, and has a negative impact on the implementation of China's sustainable development strategy.

Water pollution in China mainly comes from two aspects: one is the excessive discharge of industrial wastewater from industrial development; the other is the serious lack of urban sewage discharge and centralized treatment facilities in urbanization, and a large amount of domestic sewage directly enters the water body without treatment, causing environmental pollution. Although industrial wastewater has been reduced in recent years after treatment, the phenomenon of illegal discharge and disorderly discharge still exists. Industrial wastewater treatment is under great pressure. Urban domestic sewage has increased, accounting for more than 51% of water pollution. According to the monitoring of the environmental department, nearly 80% of the domestic sewage in the country directly enters rivers, lakes and seas without treatment, with an annual discharge of 40 billion cubic meters, causing more than one third of the water in the country to be polluted.