Last week, transit authorities activated a QR code that tracks metro passengers to aid in the prevention of the Coronavirus.
According to the Shanghai Metro official WeChat account, the number of metro riders will be significantly higher in the week beginning 2nd March at 3.6 million riders, compared to this past week which was 2.78 million riders.
Passengers are to scan the codes in the compartments of the metro cars and to enter their mobile numbers for registration. Each compartment will have a different code, and that means if passengers change cars or metro lines, they will need to re-register.
Currently, the code is available in Metro Lines 1, 2, 3, 4, 5, 6, 12, 16, the Maglev train, and Pujiang Line.
source: SHINE and 上海地铁Shmetro