The Mekong River and its tributaries are Southeast Asia’s main waterway flowing through China, Myanmar, Laos, Thailand, Cambodia and Vietnam. There are a number of dams built in the upper Mekong basin, including five in China, to generate electricity. But a second dam on river Sesan, a tributary of Mekong, is threatening the livelihood of people in Ratanakiri area of Cambodia. Activists say the dam will flood more than 30,000 hectares of farmland, forcing around 5,000 people to relocate and severely affect fishermen across the Mekong basin. The government says it has conducted all the relevant environmental surveys and believes the positive impacts outweigh the negative.