Well had you been secured even 99% still you wouldn't be getting any college by JoSAA. 

As the minumu percentage criteria in CBSE for it's eleigibilty is 75% which doesn't come under.

So I would recommend you to

1. Apply for JAC counseling. As the eligibilty here is 65% in CBSE. This is the best possible option you have.By this counsleing you will have a chance of getting a seat in the coveted seats of DTU/NSIT/IIITD as you have a decent percentile.

2. The other available option is to give an improvement in CBSE. It is also a decent option as it will not only improve your grades in X11 but also give a vital year for preparation which will ultimately enhance your performance and hence your percentile.

Refer my profile and answers to similar querries for frther references.