The Sundarbans nationwide square  is a National Park, Tiger Reserve, and a Biosphere Reserve positioned in the Sundarbans delta in the Indian state of West Bengal. This area is compactly enclosed by mangrove forests, and is one of the principal treasury for the Bengal tiger. It is also home to a variety of bird, reptile and invertebrate species, including the salt-water crocodile. The there Sundarbans National Park was declared as the core area of Sundarbans Tiger Reserve in 1973 and a flora and fauna sanctuary in 1977. On May 4, 1984 it was declared a National commons.