Wedged between Bangladesh to the south and west and China to the north, the region has no access to the sea closer than Kolkata, on the other side of the corridor. Between Sikkim and Bhutan lies the Chumbi Valley, a dagger-like slice of Tibetan territory. A Chinese military advance of less than would cut off Bhutan, part of West Bengal and all of North-East India, an area containing almost 50 million people. This situation arose during the war between India and China in 1962.