Upper Mustang is one of the very popular trekking regions in Nepal. The Home Ministry of Nepal announced the Opening of the restricted areas in October 1991.  There is also strict control in obtaining a special permit from the Department of Immigration to protect their tradition from outside influence as well as to protect the environment.  According to government rule, only organized trekking groups are allowed to trek in Mustang. The region of Tibetan influence, Kaligandaki, from the Tibetan border south to Kagbeni is generally referred to as "Upper Mustang".  The trek to Lo Manthang is through an almost tree-less barren landscape, a steep rocky trail up and down hill and panoramic views of Nilgiri, Annapurna, Dhaulagiri and several other peaks make your trek  memorable one.