So, it means that I can take admision in NSUT, DTU through the OBC quota if I submit my OBC certificate at the time of JAC counseling??

techysparta Yes u can submit them at the time of JAC counselling.For more information please read the points mentioned below.
For the validation of your obc certificate in nsit/dtu their must be two conditions satisfied:

1.Your certificate must be issued by the govt. Of nct of delhi NOT govt. Of india ,no matters on what basis it was issued by your's father obc certificate or your's brother obc certificate.

2.The caste/community from which you belong must in the list of obc caste issued by delhi govt. , which you can check here

https://www.google.co.in/url?sa=...

If you satisfied both the above 2 condition your certificate is approved for admission.

But make sure if your certificate is issued on the basis of your brother's obc certificate ,you must take his certificate at the time of document Verification at
/dtu.

Can same can be applied for obc ncl to SC