Section 172 in The Indian Contract Act, 1872
Title: "Pledge", "Pawnor" and "Pawnee" defined
The bailment of goods as security for payment of a debt or performance of a promise is called "pledge". The bailor is in this case called the "pawnor". The bailee is called the "pawnee".
Title: Pawnee's right of retainer.
The pawnee may retain the goods pledged, not only for payment of the debt or the performance of the promise, but for the interest of the debt, and all necessary expenses incurred by him in respect of the possession or for the preservation of the goods pledged.
Title: Pawnee not to retain for debt or promise other than that for which goods pledged.
The pawnee shall not, in the absence of a contract to that effect, retain the goods pledged for any debt or promise other than the debt or promise for which they are pledged; but such contract, in the absence of anything to the contrary, shall be presumed in regard to subsequent advances made by the pawnee.
Title: Pawnee's right as to extraordinary expenses incurred.
The pawnee is entitled to receive from the pawnor extraordinary expenses incurred by him for the preservation of the goods pledged.
Title: Pawnee's right where pawnor makes default.
If the pawnor makes default in payment of the debt, or performance, at the stipulated time of the promise, in respect of which the goods were pledged, the pawnee may bring a suit against the pawnor upon the debt or promise, and retain the goods pledge as a collateral security; or he may sell the thing pledged, on giving the pawnor reasonable notice of the sale.
If the proceeds of such sale are less than the amount due in respect of the debt or promise, the pawnor is still liable to pay the balance. If the proceeds of the sale are greater than the amount so due, the pawnee shall pay over the surplus to the pawnor.