By IndiaHub 
If issuing a new passport: Copies of existing OCI Card, new passport, old passport (unless the old passport has not been returned).
If OCI Card is lost/damaged: Copy of the police complaint (or equivalent report) and copy of OCI Card if available. If the complaint/report is in foreign language, an authorised translation is required.
For change of personal particulars / address / occupation: Documentary proof for the requested changes; for address proof, items like electricity bill, landline phone bill, or rent/lease agreement can be used.