Centralized isolation observation 14 days shall be carried out for those who come to Shaanxi and return to Shaanxi in high-risk areas and their counties, cities, districts, banners, municipalities directly under the Central Government and sub-provincial cities. The separation time is calculated from the time when they leave the above areas, during which four nucleic acid tests are carried out. For those who come to Shaanxi and return to Shaanxi from other counties in the city where the middle-high risk area is located, the health code and negative proof of nucleic acid detection shall be checked within 48 hours before passing. For those who travel in low-risk areas outside the above-mentioned areas, people with green health codes are not restricted from returning to China, and nucleic acid test certificates are not checked to effectively protect the normal travel needs of the people.