Gst on newly purchased flat

There is increase in tax which is now 12%. But at the same time builder is going to be benefitted from input tax credit on material reducing his cost if production substantially which was not there previously.
So if builder is not passing this benefit to consumer action may be taken against him under anti profiteering clauses of GST

Thanks for the reply, actually the developer insist to pay this gst portion. So I am asking who will pay this one the developer or the buyer ?