19. ¹[(1)] ²[If the Government is satisfied, after consultation with the Board, that it is necessary in the public interest to do so, it may, subject to such conditions, limitations or restrictions, if any, as it thinks fit to impose], by notification in the official Gazette, exempt any goods imported into, or exported from, Bangladesh or into or from any specified port or station or area therein, from the whole or any part of the customs-duties chargeable thereon ³[: Provided that if, in a financial year, exemption under this sub-section is given in respect of any goods, the rate of duty cannot be changed more than once in that year so as to increase that rate.] ⁴[(2) An exemption granted under sub-section (1) shall be effective from the date mentioned in the notification issued under that sub-section.]