Pangong Tso, Tibetan for "high grassland lake", also referred to as Pangong Lake, is an endorheic lake in the Himalayassituated at a height of about 4,350 m (14,270 ft). It is 134 km (83 mi) long and extends from India to the Tibetan Autonomous Region, China. Approximately 60% of the length of the lake lies within the Tibetan Autonomous Region. The lake is 5 km (3.1 mi) wide at its broadest point. All together it covers 604 km2. During winter the lake freezes completely, despite being saline water. It is not a part of the Indus river basin area and geographically a separate landlocked river basin. The lake is in the process of being identified under the Ramsar Convention as a wetland of international importance. This will be the first trans-boundary wetland in South Asia under the convention.
The eastern part of the lake is fresh, with the content of total dissolved solids at 0.68 g/L, while the western part of the lake is saline, with the salinity at 11.02 g/L. The brackish water of the lake has very low micro-vegetation. Guides report that there are no fish or other aquatic life on the Indian side of the lake, except for some small crustaceans. On the other hand, visitors see numerous ducks and gulls over and on the lake surface. There are some species of scrub and perennial herbs that grow in the marshes around the lake. The lake acts as an important breeding ground for a variety of birds including a number of migratory birds. During summer, the Bar-headed goose and Brahmini ducks are commonly seen here. The region around the lake supports a number of species of wildlife including the kiang and the marmot. The lake hosts large quantities of fish, especially Schizopygopsis stoliczkai and Racoma labiata. Formerly, Pangong Tso had an outlet to Shyok River, a tributary of Indus River, but it was closed off due to natural damming. Two streams feed the lake from the Indian side, forming marshes and wetlands at the edges. Strand lines above current lake level reveal a 5 m (16 ft.) thick layer of mud and laminated sand, suggesting the lake has shrunken recently in geological scale. On the Indian side, no fish have been observed, however in the stream coming from South-eastern side (Cheshul nalla), three fish species (Schizopygopsis stoliczkae, Tibetan stone loach and Triplophysa gracilis) have been reported. The low biodiversity has been reported as being due to high salinity and harsh environmental conditions.
