The Samaspur Bird Sanctuary, in the Raebareli district of Uttar Pradesh, is a perennial lowland marsh typical of the Indo-Gangetic Plains. Its six connected lakes are heavily relevant on monsoon rains. Annual counts regularly find more than 75,000 birds present, with over 250 resident and migrant species documented. The Sanctuary harbours threatened species such as the endangered Egyptian vulture (Neophron percnopterus) and Pallas's fish eagle (Haliaeetus leucoryphus), and more than 1% of the South Asian population of the vulnerable Common pochard (Aythya ferina). At least 46 freshwater fish species use the wetland, with some migrating in from nearby rivers during monsoon flood periods. The Site provides food products and agricultural fodder, as well as maintaining this biodiversity. However, invasive species threaten its ecological character, with over 40% of documented floral species being exotic.

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.