The purchaser of an estate in a district not permanently settled, 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 tenures which may have originated with the defaulter or his predecessors, being representatives or assignees of the original engager, as well as all agreements with ryots or the like settled or accredited by the first engager or his representatives, subsequently to the last settlement, as well as all tenures which the first engager may, under the conditions of his settlement, have been competent to set aside, alter, or renew, saving always and except 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, wherein mines have been sunk, which leases or engagements shall, so as the land is duly appropriated to such purposes, and the stipulated rent paid, continue in force and effect. Provided that nothing contained in this Section shall be construed to entitle any purchaser of land at a public sale for arrears of revenue to demand a higher rate of rent from any persons whose tenure or agreement may be annulled as aforesaid, than was demandable by the cases in which such persons may have held their lands under engagements, stipulating for a lower rate of rent than would have been justly demandable for the land, or in cases in which it may be proved that, according to the custom of the pergunnah, mouzah, or other local division, such persons are liable to be called upon for any new assessment, or other demand not interdicted by the regulations of Government.