Kora La is one of the oldest routes between the two regions. It was historically used for salt trade between Tibet and Nepalese kingdoms. Up until 2008
Upper Mustang was the Kingdom of Lo, an ethnic Tibetan kingdom that was a suzerainty of Kingdom of Nepal. The suzerainty allowed for a certain level of
independence in local governance from the Nepalese central government. During the late 1950s and 60s, the Tibetan guerrilla group Chushi Gangdruk operated
out of Upper Mustang with the intention of raiding PLA positions in Tibet. This led to a border incident that caused the killing of a Nepalese officer
who was mistaken by Chinese border guards as a Tibetan rebel.