Factors causing the health code to be yellow:
1, the cell phone signal will turn yellow according to your roaming record, if you find that you have been to a dangerous area or passed by.
2. If a case is detected in the community where you live on the train, the health code will turn yellow.
3. If there is abnormal data within 14 days, the health code will turn yellow.
4. People who have been quarantined for less than 14 days will have a yellow health code.
5. The hospital has a "criminal record". For example, if a person coughs and has a fever, the health code will turn yellow.