Section 3(3)(b) in The Punjab Public Moneys (Recovery of Dues) Act, 1983
(b)in every case of a mortgage, change or other encumbrance on immovable property, such property or, as the case may be, the interest therein of the person referred to in sub-section (1) shall first be sold in proceedings for recovery of the sum due from that person and any other proceedings may be taken only if the Collector certifies that there is no prospect of realisation of the sum due through the first mentioned process within a reasonable time.