The Tso Kar Basin is a high-altitude wetland complex, consisting of two principal waterbodies, Startsapuk Tso, a freshwater lake of about 438 hectares to the south, and Tso Kar itself, a hypersaline lake of 1800 hectares to the north, situated in the Changthang region of Ladakh, India. It is called Tso Kar, meaning white lake, because of the white salt efflorescence found on the margins due to the evaporation of highly saline water. The Tso Kar Basin is an A1 category Important Bird Area (IBA) as per Bird Life International and a key staging site in the Central Asian Flyway. The site is also one of the most important breeding areas of the black-necked crane (Grus nigricollis) in India. This IBA is also the major breeding area for great crested grebe (Podiceps cristatus), bar-headed geese (Anser indicus), ruddy shelduck (Tadorna ferruginea), brownheaded gull (Larus brunnicephalus), lesser sand-plover (Charadrius mongolus) and many other species. During autumn migration, the Tso Kar Basin becomes an assembling place for local breeding birds as well as a major staging spot for migrants, congregations of thousands of birds can be observed here. Apart from water birds the Tso Kar basin has been documented as the only known breeding site in India of the endangered, saker falcon (Falco cherrug). In addition to avifauna, a wide range of mammals such as the Tibetan argali (Ovis ammon hodgsoni), Tibetan wolf (Canis lupus chanko), snow leopard (Panthera uncia), Tibetan wild ass (Equus kiang) use this site and its resources.

A wetland should be considered internationally important if it contains a representative, rare, or unique example of a natural or near-natural wetland type found within the appropriate biogeographic region.

A wetland should be considered internationally important if it supports vulnerable, endangered, or critically endangered species or threatened ecological communities.

A wetland should be considered internationally important if it supports populations of plant and/or animal species important for maintaining the biological diversity of a particular biogeographic region.

A wetland should be considered internationally important if it supports plant and/or animal species at a critical stage in their life cycles, or provides refuge during adverse conditions.

A wetland should be considered internationally important if it regularly supports 20,000 or more waterbirds.

A wetland should be considered internationally important if it regularly supports 1% of the individuals in a population of one species or subspecies of waterbird.

A wetland should be considered internationally important if it supports a significant proportion of indigenous fish subspecies, species or families, life-history stages, species interactions and/or populations that are representative of wetland benefits and/or values and thereby contributes to global biological diversity.

A wetland should be considered internationally important if it is an important source of food for fishes, spawning ground, nursery and/or migration path on which fish stocks, either within the wetland or elsewhere, depend.

A wetland should be considered internationally important if it regularly supports 1% of the individuals in a population of one species or subspecies of wetland-dependent nonavian animal species.