On 10-Oct-2025, MahaRERA issued a landmark circular making Occupancy Certificate (OC) mandatory for any advertisement of ready projects. Developers must now disclose: (1) exact carpet area, (2) escrow account balance, (3) construction stage with photographs, (4) MahaRERA registration QR code, (5) penalty payable if possession delayed >6 months. Violation attracts ₹5 Cr fine and project de-registration. For buyers, this closes the old loophole where possession was offered on “partial OC”. We provide a 6-point ad verification checklist and sample complaint to RERA if any parameter is missing. Keywords: MahaRERA OC rule, buyer safeguard, property advertisement law.