Yes, request through PNB Genie app and send two years self attested ITR on mail id, followed by CIBIL hit, applicable once in six months and not before of six months membership, though they will offer upto 30% increase, so if not specific need I would recommend to stay away from them
Any specific purpose of limit enhancement on PNB card, if you want better limit go for ICICI Amazon Pay, RBL and IDFC credit card they offer almost every year limit enhancement