Based on the data collected from the country, departments and districts, through the prevention and control rules and data modeling, analysis and evaluation, three risk states of green, orange and red are calculated. In addition, foreigners need to upload photos of identity documents when applying, as well as photos taken when holding identity documents. After the system is audited, they can follow the normal process.
Take public transportation. There are records of buying plane tickets and train tickets. If there are confirmed cases in the same car or flight, you may be judged as a close contact, and the relevant departments will investigate your situation and trajectory to avoid the spread of the epidemic.