According to the Law of People's Republic of China (PRC) on the Prevention and Control of Infectious Diseases, the Emergency Regulations of Public Health Emergencies and other relevant laws and regulations, as well as the epidemic prevention regulations of relevant provinces and cities, the "three codes" of green, yellow and red are generated after automatic background verification and automatic change of applicants. Code yellow and people in red team do not meet the traffic conditions for the time being, so they need to be isolated by themselves. In order to ensure accurate status, you can click "Health Report" at the bottom of the code every day and insist on submitting a health questionnaire. After the system judges that it meets the requirements, the health code will be automatically converted into a green code, and then it can be passed.