You will receive a text message when you arrive in Nanjing.

Every time the mobile phone number goes to a city, it will be reminded by SMS, so it is not easy to turn it off. Unless your mobile phone card is not used.

This is because our cell phone signals need to be connected with cell towers in every place. Everywhere you go, people's local base stations will send messages to express their welcome to you. In the current epidemic situation, this function is very convenient, and you can know your whereabouts quickly. I hope my answer can help you.