Legal basis: People's Republic of China (PRC) Law on the Prevention and Control of Infectious Diseases.
Article 43 When Class A and Class B infectious diseases break out and become epidemic, the local people's governments at or above the county level may, upon the decision of the people's government at the next higher level, declare part or all of their administrative areas as epidemic areas; The State Council can decide and publish epidemic areas across provinces, autonomous regions and municipalities directly under the Central Government. The local people's governments at or above the county level in the epidemic area may take emergency measures as stipulated in Article 42 of this Law, and may carry out health quarantine on people, materials and means of transport entering or leaving the epidemic area.
The people's governments of provinces, autonomous regions and municipalities directly under the Central Government may decide to block the epidemic areas of Class A infectious diseases within their respective administrative areas; However, it is up to the State Council to block epidemic areas in large and medium-sized cities or across provinces, autonomous regions and municipalities directly under the Central Government, and to block trunk traffic or close borders.
The lifting of the blockade of epidemic areas shall be decided and announced by the original decision-making organ.
Article 44 When a Class A infectious disease occurs, in order to prevent the infectious disease from spreading through the means of transport and the people and articles it carries, traffic health quarantine can be implemented. The specific measures shall be formulated by the State Council.