Dear Ravi,
First of all congrats for the admission. If you qualify the required cut off for admission in Jadavpur University being in general reservation for admission then you don't require the OBC certificate. If you are qualifying the required cut off with being in the OBC reservation category then to verify that you belong to OBC category you'll require your OBC certificate.
I hope that'll help you, Best of luck with your further career prospects.
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