Hi Mukesh.

As you've got 96.6 percentile in your January JEE mains.

There's a general formula to calculate your rank(approx)  in jee mains.

Rank=(100-percentile)*869060/100

( tas far as January JEE mains is concerned)

Hence, You're general rank would be around 29,500-30,000

Hence, your approx OBC rank is

OBC-R= 0.25*G-R

Therefore, your OBC rank would be around 7,300-7,400.