Medium and high-risk cities will change color, so it is necessary to do well in advance and take high protective measures.
Health codes are based on actual data, and you can declare them online by yourself. After background review, they can generate their own personal QR code. Health codes are personal, electronic certificate. After the health code turns yellow, they need to respond in time and turn it into a green code as soon as possible.
There is no need for centralized isolation, but it will limit travel.
When the health code turns yellow, it means there is a certain risk of infection, but it doesn't mean that you are infected with COVID-19 virus. After taking some measures to eliminate the risk of infection, the health code will turn green, but before the health code turns green, it will be restricted, and some public places can not enter and leave, such as shopping malls, hotels, supermarkets, stations, airports, cinemas, KTV, bars and other public places.