A passenger passes the ticket entrance at the metro station of Wuchang Railway Station in Wuhan, central China's Hubei Province, March 28, 2020. Six metro lines in Wuhan resumed operation starting from Saturday, a new sign that life is gradually returning to normal in the hardest-hit city. Passengers are required to scan the QR code for real-name registration and take temperature checks before taking the subway. Each train is equipped with a train safety crew member to help guide and serve the passengers. (Xinhua/Cai Yang)

Passengers wait to get on the train at the metro station of Wuchang Railway Station in Wuhan, central China's Hubei Province, March 28, 2020. Six metro lines in Wuhan resumed operation starting from Saturday, a new sign that life is gradually returning to normal in the hardest-hit city. Passengers are required to scan the QR code for real-name registration and take temperature checks before taking the subway. Each train is equipped with a train safety crew member to help guide and serve the passengers. (Xinhua/Cai Yang)

Passengers are seen on the subway train of Metro Line 4 in Wuhan, central China's Hubei Province, March 28, 2020. Six metro lines in Wuhan resumed operation starting from Saturday, a new sign that life is gradually returning to normal in the hardest-hit city. Passengers are required to scan the QR code for real-name registration and take temperature checks before taking the subway. Each train is equipped with a train safety crew member to help guide and serve the passengers. (Xinhua/Cai Yang)

Passengers sit apart on the metro train in Wuhan, central China's Hubei Province, March 28, 2020. Six metro lines in Wuhan resumed operation starting from Saturday, a new sign that life is gradually returning to normal in the hardest-hit city. Passengers are required to scan the QR code for real-name registration and take temperature checks before taking the subway. Each train is equipped with a train safety crew member to help guide and serve the passengers. (Xinhua/Shen Bohan)

A train safety crew member (back) holds a placard to remind passengers of scanning the QR code for real-name registration and wearing masks on a train of Metro Line 4 in Wuhan, central China's Hubei Province, March 28, 2020. Six metro lines in Wuhan resumed operation starting from Saturday, a new sign that life is gradually returning to normal in the hardest-hit city. Passengers are required to scan the QR code for real-name registration and take temperature checks before taking the subway. Each train is equipped with a train safety crew member to help guide and serve the passengers. (Xinhua/Cai Yang)