17B. (1) Where a contract for sale of immovable property is executed but not registered prior to coming into force of section 17A- (a) the parties to the contract shall, within six months from the date of coming into force of that section,- (i) present the instrument of sale of immovable property under the contract for registration, or (ii) present the contract for sale itself for registration; or, (b) either of the parties, if aggrieved for non compliance with any of the provisions mentioned in clause (a), shall, notwithstanding anything contained to the contrary in any law for the time being in force as to the law of Limitation, institute a suit for specific performance or recession of the contract within six months next after the expiry of the period mentioned in clause (a), failing which the contract shall stand void. (2) The provision of sub-section (1) shall not apply to any contract for sale of immovable property on the basis of which a suit has been instituted in a civil court before coming into force of section 17A.]