This article originally appeared on ABACUS Shanghai is now asking subway passengers to scan a QR codes on train windows to record people’s phone numbers and and identify the train compartment they’re riding in. It “provides strong data support for tracing people in close contact with suspected patients,” Shanghai Metro posted on Weibo . The Shanghai Municipal Transportation Commission said that the QR codes will be used in all of the city’s 6,000 subway train compartments. When the new system rolled out on Friday, some Weibo users said that few people scanned the QR codes. Others also complained that the location of the QR codes on a window in the middle of the compartment is inconvenient for most passengers. China has been utilizing big data to keep tabs on people’s whereabouts in the fight against the coronavirus epidemic. Programs developed by the government and tech companies are collecting and using location data tied to real names to help alert people if they have been in close contact with confirmed or potential coronavirus cases. Purchase the China AI Report 2020 brought to you by SCMP Research and enjoy a 20% discount (original price US$400). This 60-page all new intelligence report gives you first-hand insights and analysis into the latest industry developments and intelligence about China AI. Get exclusive access to our webinars for continuous learning, and interact with China AI executives in live Q&A. Offer valid until 31 March 2020.