According to the current policy, foreign provinces and cities need to hold a 48-hour negative certificate of nucleic acid testing, and cities and counties in the state do not need to hold relevant certificates. Due to the need of epidemic prevention and control, in order to better facilitate the people, temporary nucleic acid sampling points are added in the main urban area, mainly serving people who have changed from yellow code to green code (those who have been given yellow code need to go to designated institutions for three nucleic acid tests within 7 days (each time is 24 hours apart) and 1 nucleic acid tests within 48 hours before the expiration of health monitoring on 14. If all the results are negative, they can automatically turn to green code.

Law of People's Republic of China (PRC) on the Prevention and Control of Infectious Diseases

Article 13 People's governments at all levels shall organize mass health activities, carry out health education on the prevention of infectious diseases, advocate civilized and healthy lifestyles, improve the public's awareness and ability to cope with infectious diseases, strengthen environmental sanitation construction, and eliminate the harm of rodents and vectors such as mosquitoes and flies. The administrative departments of agriculture, water conservancy and forestry of the people's governments at all levels are responsible for guiding and organizing the elimination of rodents and schistosomiasis hazards in farmland, lakes, rivers, pastures and forest areas, as well as the hazards of other animals and vectors that spread infectious diseases. The administrative departments of railways, transportation and civil aviation shall be responsible for organizing the elimination of rodents, mosquitoes, flies and other vectors in vehicles and related places.

Article 14 Local people's governments at all levels shall build and transform public health facilities in a planned way, improve the sanitary conditions of drinking water, and treat sewage, dirt and feces harmlessly.

Article 15 The state practices a planned immunization system. The administrative department of health in the State Council and the people's governments of provinces, autonomous regions and municipalities directly under the Central Government shall, according to the needs of infectious disease prevention and control, formulate plans for infectious disease vaccination and organize their implementation. Vaccines used for vaccination must meet the national quality standards. The state implements a vaccination certificate system for children. Vaccination in the national immunization program is free. Medical institutions, disease prevention and control institutions and guardians of children should cooperate with each other to ensure that children receive vaccination in time. The specific measures shall be formulated by the State Council.