Big Data sent a close connection at 7pm, what’s going on?

Generally, it is because your mobile phone signal and the mobile phone signal of the confirmed person stay in the same time and space for more than a certain period of time.

Big data close contacts are determined through technical means and are people who have had time and space intersection with confirmed cases. Some other cities are also called "time and space companions". You don’t need to worry too much. Big data close contacts are different from close contacts in the medical sense. The risk is generally not as great as close contacts or sub-close contacts. However, due to uncertainty, you still need to cooperate with health management measures of home medical observation. The detection of big data close connections is limited and not so precise. It is only possible to see which province or city the itinerary is in.