Call recording

I have seen a movie recently. In the movie, they have shown like TRAI would record all the phone conversations and the court can request TRAI for those past call recordings. If it is true, service providers would need TBs of data and huge servers? So, I wanted to get to know the facts in this though it was shown in a movie. 1) Every phone call(All Citizens) conversation is recorded as an audio file and stored by the service providers? If it is true how long the data is stored? 2)CDR is both call recording audio file & digital timestamps? or Only Digital time stamps of a call? 3) What is the level of authority that can have CDR of an individual? 4)What are the actual contents(details) provided in CDR by Telecom Service Provider? 5)to be clear enough, what do our laws saying on recording a phone call conversation? 6) (If the recording does not default) If any government authority needed who will give permission to do that? Under what circumstances? 7)Without government authority guidelines, Can the service provider record the phone conversation of a citizen?