Lower price in sale deed to reduce registration charges

to save the stamp duty and registration charges people shows the purchase value of their property in the sale deed at the circle rate but in reality they paid the seller at the rate of market value which is of very higher side then that what he mentioned in their sales deed in this way both seller and purchaser saves money , but the purchaser forgot or not knows that how big loss he is doing knowengly or unknowingly for himself , unfortunately if some mishappening happen to his property like earthquake or other disaster or govt. acquire the land or property then the govt. will pay him at the rate on which he had paid the stamp duty i.e on the circle rate , then here he is a big looser, therefore always pay the stamp duty and registration charges on your actual paid money to the seller .