Trek Mustang with Saribung Peak (6330m) climbing Punakha - Thimphu sightseeing | 76 km | Drive: 3 hours | Altitude: 2334 m. Day 9. Relations with Nepal remained strained due to Bhutanese refugees. Per capita income (PPP) is around $7,641,[53] ranked 144th. The industrial sector is currently in a nascent stage. Also, it covers most of the world with an absolute vertical height accuracy of less than 16m. [143] The production of ferrosilicon was pioneered by Damchae Dem, CEO of Pelden Group. National carrier Drukair operates flights between Paro Airport and Bathpalathang Airport in Jakar (Bumthang Dzongkhag), central Bhutan, Gelephu Airport in Gelephu (Sarpang Dzongkhag) in the south and Yongphulla Airport in the east (Trashigang Dzongkhag) on a weekly basis. Bhutan does not have formal diplomatic ties with China, but exchanges of visits at various levels between them have significantly increased in recent times.