The authors discuss the significance role of mountains in sustaining water availability in the future, especially in densely populated tropics and subtropics located in hydrogically sensitive zones. They emphasize the support provided by mountain wetlands as well as identifies mountain wetlands into herbaceous wetlands, peatlands, and riparian wetlands. Particular focus is given to the low elevation freshwater swamps in the low-lying valleys of the Western Ghats and foothills of the Himalayas.