Water quality affects the health of people and environment, especially in areas where sanitation is not adequate. Water can be clean at the point of production but contaminated at the point of delivery. Bacteriological contamination of surface water represents a serious issue in South Asia. Diarrhea and worm infestations are the two major waterborne health threats in the region. It is estimated that diarrhea kills about 110,000 Bangladeshi children under age five each year. The situation is even worse in India, Nepal, and Pakistan. Industrial and agricultural runoff along with untreated waste contaminating water that is eventually used for drinking and cooking represent an important health issue.
Naturally-occurring arsenic contamination of groundwater also poses a serious challenge in the region. High concentrations of arsenic detected in groundwater in a number of aquifers in South Asia, have been found responsible for health problems ranging from skin disorders to cardiovascular disease and cancers. These health problems are collectively referred to as "arsenicosis." Drinking water is one of the principal modes of arsenic exposure in humans. Cooking food or irrigating crops with water that has a high arsenic content may also lead to the development of arsenicosis. It is estimated that around 65 million people live in arsenic risk-prone areas in Asia (Arsenic Contamination of Groundwater).
The determination of water quantity and quality needed to sustain an ecosystem, including the human livelihoods that depend on it, is of critical importance. In addition to being depleted by intense water use for crop and food production, river flows are also affected by fluctuations in water levels between the rainy and dry seasons. Oftentimes, people living upstream benefit from river flows at the expense of those who are downstream. Extensive withdrawals upstream have a negative impact on the ecology of the downstream area. Thus, it is very important that enough water remain in rivers and lakes to maintain downstream ecosystems and ensure environmental, social and economic benefits there.
Wetlands are among the most productive ecosystems in the world, comparable to rain forests and coral reefs. An immense variety of microbes, plants, insects, amphibians, reptiles, birds, fish, and mammals are part of a wetland ecosystem. South Asia has many wetlands that vary in altitudes from coastal wetlands to the foothills of the Himalayas.
Wetlands are under threat of degradation or disappearance due to unsustainable development, which have great impact on the local communities.