47. (1) Any person liable to the payment of betterment fee may, at his option, instead of making a payment thereof to the Authority, execute an agreement with the Authority to leave the said payment outstanding as a charge on his interest in the land, subject to the payment in perpetuity of interest at the rate of six per cent per annum, the first annual payment of such interest being made on the expiry of one year from the date fixed under section 46. (2) Every payment due from any person in respect of a betterment fee and every charge referred to in sub-section (1) shall, notwithstanding anything contained in any other law for the time being in force, be the first charge upon the interest of such person in such land.