Hello Harsh,

As per the official guidelines of GATE authority mentioned in the brochure, producing caste/category certificate is mandatory for availing the benefits of the same. So if you have not submitted the OBC-NCL certificate at the timer of your application you will be considered in GEN or OPEN category and you'll not be able to avail the concession given to the students belonging to the same throughout the course you have taken admission for.

Hope it helps.