Passengers are seen at a subway station in Shanghai, Feb.28, 2020. The QR code which tracks passengers is introduced to Metro trains in the city. Passengers who scan the code and enter their mobile phone number in an app will be contacted for the purpose of prevention of the spread of coronavirus. (Photo: China News Service/Yin Liqin)
A view of a subway car in Shanghai, Feb.28, 2020. The QR code which tracks passengers is introduced to Metro trains in the city. Passengers who scan the code and enter their mobile phone number in an app will be contacted for the purpose of prevention of the spread of coronavirus. (Photo: China News Service/Yin Liqin)
A view of a subway car in Shanghai, Feb.28, 2020. The QR code which tracks passengers is introduced to Metro trains in the city. Passengers who scan the code and enter their mobile phone number in an app will be contacted for the purpose of prevention of the spread of coronavirus. (Photo: China News Service/Yin Liqin)
