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 are distinct from the other great ranges of central Asia, although sometimes the term Himalaya (or Greater Himalaya) is loosely used to include the Karakoram and some of the other ranges. The Himalayas are inhabited by 52.7 million people and are spread across five countries: Nepal, India, Bhutan, China and Pakistan. Some of the world's major rivers — the Indus, the Ganges and the Tsangpo-Brahmaputra — rise in the Himalayas, and their combined drainage basin is home to roughly 600 million people. The Himalayas have a profound effect on the climate of the region, helping to keep the monsoon rains