This is a dam that borders Nepal and India. It is mainly used to control the water flowing from Nepal into India. During rainy season there's plentiful of rainfall that causes increase in water level and there's excessive flow of water from Nepal into India due to which India may get drowned. That's why, the dam is blocked in rainy season. This in return causes flooding of villages in Nepal.

While in summer the dam is opened, this aids people of India to irrigate the land while Nepalese suffer from water scarcity in their land. 

In both way, Nepal has to suffer. 

And now, due to excessive deposition of household and industrial wastes plus drainage, the quality has entirely degraded and eutrophication, land pollution, air pollution and water pollution is the ultimate result. People are working to reduce it but the pace is far slower as tortoise speed.

Policies and plans should be made in such a way that both the nations are equally benefited.