Pallikaranai wetland is a freshwater marsh in the city of Chennai, India. It is situated adjacent to the Bay of Bengal, about 20 kilometres south of the city centre, and has a geographical area of 1247.54 ha. The marshland is located along the Coromandel Coast south of the Adyar Estuary, serving as an aquatic buffer of the flood-prone Chennai and Chengalpattu districts. It is surrounded by the expressway of Old Mahabalipuram Road and the residential areas of Perungudi, Siruseri, Pallikaranai, Madipakkam, Velachery and Taramani. The heterogeneous ecosystem of the marshland support faunal groups such as birds, fishes, and reptiles are the most prominent. Pallikaranai marsh is home to 115 species of birds, 10 species of mammals, 21 species of reptiles, 10 species of amphibians, 46 species of fishes, 9 species of molluscans, 5 species of crustaceans, and 7 species of butterflies. It is also home to some of the most endangered reptiles such as Russell\\\'s viper and birds such as the glossy ibis, grey-headed lapwings, and Pheasant-tailed jacana. Cormorants, darters, herons, egrets, open-billed storks, spoonbills, white ibis, little grebe, Indian moorhen, black-winged stilts, purple moorhens, warblers, coots, and dabchicks have been spotted in large numbers in the marshland.

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.