Hello Aspirant,

Hope you are having  a great day.
Yes, definitely you can pursue the PhD degree without qualifying CSIR JRF, but you will have to qualify the written tests and interviews of the respective Universities of Institutes. In this case, unless you have a sponsor the entire expenses of pursuing PhD shall have to be fulfilledby you.

The advantage of qualifying for  JRF is that you will be funded as a scholarship or researcher by the government or institution through your PhD. This is very commendable. However, you can also get a PhD without a JRF qualification.

Hope this answer helps you.
Good luck for future endeavors!!