Central Teacher Eligibility Test, CTET is a national level exam conducted by CBSE twice a year, namely in July and December every year. The July 2020 CTET has been postponed due to the COVID-19 outbreak, which was supposed to be held on July 5 .
In the year 2019, for CTET December Session, the application process started in mid August and was open till Sep 30. As the current situations are different, so the process may start somewhat later in August or September. So you need to visit the official website regularly