birth place mumbai & native is UP & frm there i falls in obc categry but all my documnet & edu is frm mumbai so i can apply obc or not CAT

For CAT Exam, Your Category must be according to as the central government specified list. You can visit for an updated central list of state - wise OBCs eligible for availing the benefit of reservation and information in respect of the creamy layer, visit the website http://www.ncbc.nic.in.

In case of NC - OBC category, the castes included in Central List (available at http://www.ncbc.nic.in) of NC - OBC by the National Commission of Backward Classes, Government of India as on last day of registration will be used.

So kindly check above-mentioned websites for your category according to central list.