The purchaser .of an entire estate in the permanently settled Districts of Bengal, Behar, and Orissa, sold under this Act for the recovery of arrears due on account of the same, shall acquire the estate free from all encumbrances which may have been imposed upon it after the time of settlement; and shall be entitled to avoid and annul all under-tenures and forthwith to eject all undertenants, with the following exceptions:
    First. Istemraree or mokurreree tenures which have been held at a fixed rent from the time of the permanent settlement.
    Secondly. Tenures existing at the time of settlement, which have not been held at a fixed rent.     Provided always that the rents of such tenures shall be liable to enhancement under any law for the time being in force for the enhancement of the rent of such tenures.
    Thirdly. Talookdaree and other similar tenures created since the time of settlement and held immediately of the proprietors of estates, and farms for terms of years so held, when such tenures and farms have been duly registered under the provisions of this Act.
    Fourthly. Leases of lands whereon dwelling houses, manufactories, or other permanent buildings have been erected, or whereon gardens, plantations, tanks, wells, canals, places of worship, or burning or burying grounds have been made, or wherein mines have been sunk.
    And such a purchaser as is aforesaid shall be entitled to proceed in the manner prescribed by any law for the time being in force for the enhancement of the rent of any land coming within the fourth class of exceptions above made, if he can prove the same to have been held at what was originally an unfair rent, and if the same shall not have been held at a fixed rent, equal to the rent of good arable land, for a term exceeding twelve years; but not otherwise.
    Proviso.---Provided always that nothing in this Section contained shall be construed to entitle any such purchaser as aforesaid to eject any ryot having a right of occupancy at a fixed rent or at a rent assessable according to fixed rules under the laws in force, or to enhance the rent of any such ryot otherwise than in the manner prescribed by such laws, or otherwise than the former proprietor, irrespectively of all engagements made since the time of settlement, may have been entitled to do.