The “Health Code” means, if Red, you are likely to have the virus; Yellow means you have been in contact with the virus and are unable to travel; and Green means you are unrestricted. In many cases, citizens have to present the smartphone QR code for scanning at checkpoints, before entrance-ways and turnstiles, before they are allowed to progress into railway and subway stations, as well as hotels, restaurants and entertainment venues (even gaining entry into apartment blocks and offices). Some sources are suggesting this scheme is already being used in 200 Chinese cities, and growing. The program sends information to law enforcement regarding those breaking app-based quarantining.