If the results of nucleic acid detection are negative for three consecutive times (the interval between the two times is more than 24 hours) after the critical period in which the confirmed cases and asymptomatic infected persons may contact, you can apply for decoding, and the system will remove the yellow code and turn it into a green code.
The reason why the yellow code is said is that the health code has moved and stayed near the key places where the confirmed cases and asymptomatic infected people have stayed, and may have had contact with the confirmed cases and asymptomatic infected people, so it is included in the scope of the yellow code. The health code is yellow, so as to minimize traffic and consciously suspend group activities such as dinner and participation.