As of my last update in September 2021,22,23, Anna University in Chennai, India, does not have a strict campus-wide ban on mobile phones. However, the use of mobile phones might be restricted in certain areas such as classrooms, examination halls, and libraries, to maintain a conducive academic environment. These restrictions are common in educational institutions worldwide to minimize distractions during lectures, exams, and study sessions. It's important to note that rules and policies can change, so it's advisable to check the official website of Anna University or contact the university directly for the most current and specific information regarding the use of mobile phones on campus.