The green code becomes a passport to every place every day, and the health code indicates to visit here every time the location code is scanned. If your daily trajectory is abnormal, if your body temperature is registered abnormally, and your place is registered as a medium-high risk area, then your passport will no longer be applicable and you can only be isolated at home.
Double green codes refer to health codes and city travel codes. Health codes are based on real data and can be generated by citizens or people who have returned to work through online declaration and background audit. As an individual entering and leaving electronic certificate locally, the QR code can be declared once, which is universal in the whole city.