Contract Act (9 of 1872) , S.72— Contract for supply of gas - Price escalation by seller - Escalation challenged - Court by interim order directing seller to continue supply only at original price - Enhancement finally found valid - Purchaser liable to pay difference in price as well as interest for delayed payment - Principles of deemed renewal of contract and restitution apply. Civil P.C. (5 of 1908) , S.144— Agreement for supply of natural gas were entered into between the ONGC and different industries. The agreement stipulated the price, mode of payment and also the interest payable in case of delay in payment. After the expiry of the term of these agreement, ONGC the supplier proposed that the contract should be renewed but at the enhanced price. The purchaser thereon challenged the increase in the price of gas as fixed. By an interim order, the Court directed the supplier to supply gas as the old rate. The escalation in price made by ONGC was finally found to be valid by Court. ONGC the seller thereupon demanded from the purchasers the difference in price and also interest for delayed payment at the rate stipulated in the agreement. The claim made for interest was disputed by the purchasers. Held, ONGC was entitled to claim interest from the purchasers for the delayed payment of the principal amount.(Para 11 ....