4. Ganges River Dolphin
The Ganges River Dolphin used to exist in large numbers near the urban centers in both the Ganges and Brahmaputra rivers and was declared India's National Aquatic Animal in 2009.
Their numbers have now dwindled to a quarter of their numbers fifteen years ago. There are several marine dolphins, whose ranges include some freshwater habitats, but there are only four dolphin species that live only in freshwater rivers and lakes and Ganges river dolphin is one of them.