Sub section (1) of section 18 is: "(1) Where the rights of an evacuee in any land 155 or in any house or other building consist or consisted of occupancy rights, nothing contained in any law for the time being in force or in any instrument having the force of law or in any decree or order of any court, shall extinguish or be deemed to have extinguished any such rights either on the tenant becoming an evacuee within the meaning of this Act or at any time thereafter so as to prevent such rights from vesting in the Custodian under the provision of this Act or to prevent the Custodian from exercising all or any of the powers conferred on him by this Act in respect of any such rights, and, notwithstanding anything containd in any such law, contract, instrument, decree, or order, neither the evacuee nor the Custodian, whether as an occupancy tenant or as a tenant for a certain time, monthly or otherwise, of any land or house or other building shall be liable to be ejected or be deemed to have become so liable on any ground whatsoever for any default of (a) the evacuee committed after he became an evacuee or within a period of one year immediately preceding the date of his becoming an evacuee; or (b) the Custodian." The expression 'occupancy rights ' has not been defined in the Act.