(210128) -- XI'AN, Jan. 28, 2021 (Xinhua) -- A passenger scans the health tracking QR code as she enters Xi'an Railway Station, in Xi'an, northwest China's Shaanxi Province, Jan. 28, 2021. The Spring Festival travel rush, known as the world's largest annual human migration, lasts 40 days from Jan. 28 to March 8 this year. (Xinhua/Li Yibo)
