What does it mean that the coding date changes every three days?

After entering the new area, you will receive health reminder information first, and then the health code will be assigned a yellow code, which will be assigned for more than 7 days. If there is no exception, it will automatically turn into a green code. The personnel assigned the yellow code should actively cooperate with the local community to implement the work requirements of "three days and two inspections". "Two tests in three days" means two nucleic acid tests in three days.