Once you pay the tax on the capital gains, there is no restriction on the usage of the sale proceeds after investing in assets like house/bonds, if claimed by you. As the amount is already in the bank account, there is no restriction on holding the cash. However, if you are referring to any cash receipts in addition to the sale consideration mentioned in the sale deed, such cash receipts become taxable too. As per the newly introduced Section 269ST, no person shall receive cash for Rs 2 Lakhs or more towards financial transactions. So if you are receiving cash, it will be in violation of Section 269ST of the Income Tax Act.