The main legal point established in the judgment is the entitlement of O.N.G.C. to claim interest from the respondents based on the implications of the agreements and the principle of restitution.

Judgment

KIRPAL, J.

( 1 ) THE only question which arises for consideration in these applications filed by the Oil and Natural Gas Commission (for short "ongc") relates to the demand of interest from the respondents subsequent to the appeal with regard to fixation of price of natural gas having been decided by this Court.

( 2 ) BRIEFLY stated the facts are that the respondents had entered agreements with the applicant whereby they had agreed to take natural gas from the applicant for the purpose of the industries run by them. It is not in dispute that there were written contracts executed between the applicant on the one hand and the various companies, namely, the respondents on the other. The agreements, in question, have stipulated the price payable and also contained terms inter alia to the effect as to when payment would be made and, in the event of failure to make the payment, the rate of interest which would be paid. This was provided in clauses similar to Clause 5. 01 read with Clause 5. 02 which reads as follows :"5. 01. The SELLER shall issue and send to the BUYER invoices covering the total quantity of GAS delivered hereunder by the SELLER during each month for payment. The BUYER shall pay in full within ten (10) days of the receipt of such invoice the amount so mentioned in such invoices. For this purpose a month would commence at 0700 hours of first day of "a month" and end at 0700 hours of the first day of the following month. In case there is any dispute regarding the quantities of GAS supplied, the BUYER shall not withhold payment on this ground. After making full payment, the BUYER shall lodge his claims to the SELLER giving full particulars within a period of (14) fourteen days from the date of making the payment. 5. 02. The BUYER shall pay interest on all delayed payments at the rate of half (1/2) per cent higher than the rate of interest payable by the SELLER on cash credit facility from the State Bank of India from time to time. Delayed payment means any payment not received within the period in Clause 5. 01 mentioned above. "

( 3 ) THE contracts came to an end on 30/03/1979 and the applicant proposed that the contract should be renewed but at the enhanced price of gas. The respondents there upon filed a writ petition before the Gujarat High Court challenging the increase in the price of gas as fixed. By an interim order, the High Court directed the applicant to supply gas at the old rate of Rs. 504. 00 per 1000m3. Subsequently, by an order dated 29/10/1982, the High Court increased the interim price to Rs. 1000. 00 per 1000m3.

( 4 ) BY judgment dated 30/07/1983, the High Court allowed the writ petition and set aside the price which had been determined by the applicant. Pursuant to a certificate of fitness having been granted, appeals were filed in this Court. The interim orders of the High Court continued to remain in operation and the respondents received the gas for which it paid interim price of Rs. 1000. 00 per 1000m3.

( 5 ) BY judgment dated 4/05/1990 reported as 1990 Suppl SCC 397 : (AIR 1990 SC 1851), this Court upheld the prices fixed by the applicant and allowed the appeals filed by O. N. G. C.

( 6 ) DURING the pendency of these appeals, on 15/04/1987, an interim order was passed which was similar in terms to the one which had been passed by the High Court, namely, that the supply of gas to the respondents shall not be discontinued and they would be charged at the rate of Rs. 1000. 00 pre 1000 cubic metres.

( 7 ) AFTER the appeals were allowed, the applicants herein became entitled to receive the difference in the price of gas. The applicants in addition to the said principal amount also demanded interest thereon in terms of the aforesaid clause 5. 02. When payment was not made, IA Nos. 1-11 and 23-33 were filed in this Court. On 6th of April, 1993, this Court considered the case of the respondents and put them in three different categories. It is not necessary to deal with this in any great extent ex