Eastern South Asia region is bounded by Nepal, Sikkim, and Bhutan in the north, Bangladesh in the east, the Indian states of Uttar Pradesh and Chhattisgarh on the west, and the Indian state of Andhra Pradesh in the south. It is connected to the Seven Sister States of Northeast India by the narrow Siliguri Corridor. West Bengal is on the eastern bottleneck of India, stretching from the Himalayas in the north, to the Bay of Bengal in the south. The region lies in the humid-subtropical zone. The landlocked region of Northeast India includes the states of Assam, Arunachal Pradesh, Bihar, Mizoram, Manipur, Meghalaya,
Himalayas of the northernmost bend of Indus river. Its eastern anchor, Namcha Barwa, is just west of the great bend of the Yarlung Tsangpo River (upper stream of the Brahmaputra River). The Himalayan range is bordered on the northwest by the Karakoram and the Hindu Kush ranges. To the north, the chain is separated from the Tibetan Plateau by a wide tectonic valley called the Indus-Tsangpo Suture. Towards the south the arc of the Himalaya is ringed by the very low Indo-Gangetic Plain. The range varies in width from in the west (Pakistan) to in the east (Arunachal Pradesh). The Himalayas