If your area is a closed or controlled area, the health code may be "marked with an asterisk" or a yellow code. When an asterisk appears, it indicates that you have been to or are at risk of urban epidemic in the past 14 days. Level modulation belongs to the middle and high risk area, that is, there are confirmed cases.
If the confirmed case is far away from you and your area is out of control, the health code will not affect it.