The decision to halt or restrict air travel to and from any country is typically based on several factors, including public health concerns, international guidelines, government policies, and risk assessments. While specific measures may vary depending on the situation, here are some reasons why air travel to and from China, or any country, may not be completely halted:

1. Risk Assessment: Governments and health organizations assess the risk of disease transmission based on factors such as the severity of the outbreak, the effectiveness of containment measures, and the level of community spread. If the risk is deemed manageable and can be mitigated through various measures, complete halting of air travel may not be necessary.
2. Essential Travel: Halting all air travel can have significant economic, social, and humanitarian implications. There may be a need to ensure that essential travel, such as repatriation flights, transportation of medical supplies, and diplomatic missions, can continue.
3. Travel Restrictions and Precautions: Instead of a complete halt, countries may implement travel restrictions, such as screening measures, health declarations, quarantine protocols, or requirements for negative COVID-19 test results. These measures aim to mitigate the risk while allowing necessary travel to continue.
4. International Guidelines and Coordination: The World Health Organization (WHO) and other international bodies provide guidelines and recommendations for managing disease outbreaks and air travel. Countries often coordinate their response efforts and follow these guidelines to ensure a harmonized approach.

It’s important to note that decisions regarding air travel restrictions are made by governments in collaboration with public health agencies, taking into account multiple factors such as public safety, global health considerations, economic impact, and international obligations. These decisions may be reviewed and updated based on the evolving situation and new information about the outbreak.