Passengers perform self-service check-in process at Terminal 2 building of the Shanghai Pudong International Airport in east China's Shanghai, Nov. 24, 2020. The airport's recent daily throughput maintains at around 1,000 flights, with passengers wearing face masks and orderly moving in and out. (Xinhua/Ding Ting)

Passengers pass security checkpoint at Terminal 2 building of the Shanghai Pudong International Airport in east China's Shanghai, Nov. 24, 2020. The airport's recent daily throughput maintains at around 1,000 flights, with passengers wearing face masks and orderly moving in and out. (Xinhua/Ding Ting)

Passengers check in at the domestic departure section of Terminal 2 building of the Shanghai Pudong International Airport in east China's Shanghai, Nov. 24, 2020. The airport's recent daily throughput maintains at around 1,000 flights, with passengers wearing face masks and orderly moving in and out. (Xinhua/Ding Ting)

Passengers perform self-service personal health confirmation at Terminal 2 building of the Shanghai Pudong International Airport in east China's Shanghai, Nov. 24, 2020. The airport's recent daily throughput maintains at around 1,000 flights, with passengers wearing face masks and orderly moving in and out. (Xinhua/Ding Ting)