The TET, or Teachers Eligibility Test, is a must for teachers because this is a good way to judge whether someone has the skills needed to be a teacher. A good or bad teacher can make or break a student. It is very important to make sure that a teacher is qualified.
Adding yet another exam and another hurdle to becoming a teacher is not the answer to education system problems. Teachers need to be chosen based on their performance, which is something best monitored by their supervisor as is done at other places of work. While there have to be some basic educational requirements, we are currently lacking enough teachers, and the way to get better teachers is to improve compensation and provide adequate support for current, new and prospective teachers. Increasing the number of people that want to teach would allow the hiring officials a wider pool to select from and improve motivation and job performance.