"If you only pass through high-risk areas, such as taking trains, high-speed trains, cars and other means of transportation, then the health code will not change color, but if you stay in high-risk areas for a period of time, the health code is likely to change color, and you should report it in time if you find that the health code changes color."
High risk areas generally refer to high risk areas. High-risk areas, that is, counties and cities (districts) as a unit, have accumulated more than 50 cases, and a cluster epidemic occurred within 14 days.