> You can't register a hut in the property registration office since a decade without a PAN number. And builders haven't been taking cash since more than a decade now.

Where I stay(Mumbai suburb), taking some percentage of money as cash was always the norm. For example, for a flat worth 90 lakhs, you were expected to pay 60-75 lakhs in white and the rest in black(cash). This inflated the costs and many folks could not afford a flat due to this. It's mostly gone now thanks to RERA but Demo also played some part.