The asterisk after travel itinerary indicates that there are medium-risk or high-risk areas in the cities you pass through or visit, but it does not mean that you have actually visited these medium-risk or high-risk areas. "Passing by" means staying in a place for more than 4 hours. When you open the itinerary code with your mobile phone, the system will automatically record it as passing by or visiting. The itinerary card is updated every day. The "Communication Big Data Travel Card" service was jointly launched by China Information and Communication Research Institute of the Ministry of Industry and Information Technology and three major telecom operators. Using the communication big data of China Telecom, China Mobile and China Unicom, it provides travel inquiry service for 654.38+06 billion mobile phone users nationwide.