Teesta river is 414 km long with a total catchment area of 12,159 km2. Teesta basin is home to around 30 million people, 2% in Sikkim, 27% in West Bengal; and 71% in northwest Bangladesh of which 78% are rural and 22% urban. Sikkim is mountainous with very low population density, whereas West Bengal has a mix of low hills and plains, and in Bangladesh the terrain is almost flat. There are two large barrages on Teesta that diverts water for mainly irrigation purpose: one at Gajoldobha in India and the other at Duani in Bangladesh.