Tourists shop at a duty-free shopping mall in Sanya City, south China's Hainan Province, Oct. 5, 2020. Hainan is witnessing a boom in duty-free sales during this National Day and Mid-Autumn Festival holiday. (Xinhua/Guo Cheng)

Tourists shop at a duty-free shopping mall in Sanya City, south China's Hainan Province, Oct. 5, 2020. Hainan is witnessing a boom in duty-free sales during this National Day and Mid-Autumn Festival holiday. (Xinhua/Guo Cheng)

Tourists shop at a duty-free shopping mall in Sanya City, south China's Hainan Province, Oct. 5, 2020. Hainan is witnessing a boom in duty-free sales during this National Day and Mid-Autumn Festival holiday. (Xinhua/Guo Cheng)

Tourists shop at a duty-free shopping mall in Sanya City, south China's Hainan Province, Oct. 5, 2020. Hainan is witnessing a boom in duty-free sales during this National Day and Mid-Autumn Festival holiday. (Xinhua/Guo Cheng)

Tourists shop at a duty-free shopping mall in Sanya City, south China's Hainan Province, Oct. 5, 2020. Hainan is witnessing a boom in duty-free sales during this National Day and Mid-Autumn Festival holiday. (Xinhua/Guo Cheng)

Tourists shop at a duty-free shopping mall in Sanya City, south China's Hainan Province, Oct. 5, 2020. Hainan is witnessing a boom in duty-free sales during this National Day and Mid-Autumn Festival holiday. (Xinhua/Guo Cheng)