Reverse charge on promoters for shortfall purchases in real estate projects makes promoters liable to pay GST received from unregistered suppliers. Notification imposes reverse charge liability on a registered promoter to pay tax for supplies received from unregistered suppliers that constitute the shortfall from minimum purchases required for a real estate project (or until completion/first occupation), specifically covering certain goods and services, cement under chapter 2523, and capital goods supplied for construction where tax is payable at prescribed real estate rates.