The Kazhuveli Bird Sanctuary covering an area of 5151.6 ha was declared as the 16th bird sanctuary in Tamil Nadu in the year 2021. It is a brackish shallow lake located on the Coromandel Coast in Villupuram district, North of Pondicherry. The lake is connected to the Bay of Bengal by the brackish Uppukalli creek and the Edayanthittu Estuary. Kazhuveli is one of the significant and biodiversity rich wetlands. The lake is one of the largest wetlands in peninsular India. The lake can be divided into three parts based on the water features viz., the estuarine part with brackish water, the Uppukali creek feeding the sea water and the Kazuveli basin with fresh water. The Kazhuveli wetland lies in the Central Asian Flyway and is an important stopover site for migratory species of birds and breeding ground for resident species of birds, breeding ground for fish and serves as a major recharge source for the aquifers. In areas of brackish water highly degraded mangrove patches containing Avicennia species are found. In the earlier years, this area was reportedly harbouring Tropical Dry Evergreen Forests. In this area, reed (Typha angustata) is found in several hundred hectares.

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.