Tibet's foreign trade fell by 59.2 percent at 5.66 billion yuan (861 million U.S. dollars) in 2015, according to the latest data.
Exports of the southwestern autonomous region dropped 71.9 percent to 3.6 billion yuan, while imports were up 114.4 percent at 2.03 billion yuan, according to the Lhasa Customs.
The decrease was mainly caused by the massive earthquake in Nepal last year, which blocked the highway to Zham, the border township where 90 percent of China-Nepal land trade had been conducted, according to customs staff.
Nepal has remained Tibet's top trade partner since 2006. In 2014, Tibet's trade with Nepal exceeded 10 billion yuan, accounting for 90 percent of the region's total foreign trade that year.