JUDGMENT

MADON, J.:— These two Appeals by Special Leave granted by this Court raise a common question of law as regards the maximum amount of pension for superior service admissible under clause (b) of sub-rule (1) of Rule 299 of the Hyderabad Civil Services Rules. According to the Appellant in each of these two appeals, such amount is Rs. 1,000 per month while according to the State of Andhra Pradesh, the Respondent in both these Appeals, it is Rs. 857.15 pet month.

2. Before considering which of these two rival contentions is correct, it would be convenient to relate first the relevant facts which have given rise to this controversy.

3. Prior to the coming into force of the Constitution of India on January 26, 1950, Hyderabad was an Indian State within the meaning of that term as defined in Section 311 (1) of the Government of India Act, 1935, and its Ruler within the meaning of that term as defined in the said Section 311(1) was the Nizam. The Appellant in Civil Appeal No. 2627 of 1977, Ahmed Hussain Khan, joined the service of the Public Works Department of the erstwhile Indian State of Hyderabad in the year 1945 and retired on April 5, 1972, as Chief Engineer, Electricity (Operation), Andhra Pradesh State Electricity Board. At the time of his retirement he was drawing a salary of Rs. 1,980 per month. By a Government Order, namely, G. O. MS No. 664, Public Works (E) Department, dated June 22, 1973, this Appellants pension after deducting the pension equivalent of death-cum-retirement gratuity was fixed at Rs. 801.96 per month on the basis that the maximum amount of pension admissible under Rule 299(1)(b) of the Hyderabad Civil Services Rules was Rs. 1,000 per month. By another Government Order, namely, G. O. MS No. 769, Public Works (Pen. I) Department, dated July 2, 1973, the amount of pension payable to this Appellant was fixed at Rs. 683.11 per month after deducting the pension equivalent of death-cum-retirement gratuity on the basis that by a Notification dated February 3, 1971, amending the said clause (b) of Rule 299 (1), the amount of maximum pension admissible under the said clause was restricted to Rs. 857.15. Ahmed Hussain Khan thereupon filed a writ petition under Article 226 of the Constitution of India in the High Court of Andhra Pradesh, being Writ Petn. No. 7113 of 1973, challenging the said amendment made to clause (b) of Rule 299(1) inter alia on the ground that under the proviso to sub-section (7) of section 115 of the States Reorganisation Act, 1956, the said amendment required the previous approval of the Central Government which had not been obtained.

4. The Appellant in Civil Appeal No. 2628 of 1977, S. Gopalan, joined the service of the Public Works Department of the erstwhile Indian State of Hyderabad in the year 1942 and retired on April 14, 1973, as Chief Engineer, Major Irrigation and General Public Works Department, Government of Andhra Pradesh. At the time of his retirement he was drawing a salary of Rs. 2,180 per month. By a Government Order, namely, G. O. MS No. 462, P. W., (L1) Department, dated May 8, 1973, his pension was fixed at Rs. 857.15 per month pursuant to the said amended clause (b) of Rule 299(1). He thereupon filed a writ petition under Article 226 of the Constitution of India in the High Court of Andhra Pradesh, being Writ Petition No. 7114 of 1973, on the same grounds as the Appellant Ahmed Hussain Khan.

5. Both these writ petitions were heard together and disposed of by a common judgment by a learned single Judge of the said High Court. The aforesaid contention raised in the said writ petitions found favour with the learned single Judge and he allowed both the said writ petitions and issued a writ of mandamus in each of them directing the State of Andhra Pradesh to fix the pension payable to the Appellant in each of these two Appeals from the date he became eligible for pension, that is, from the date on which he retired from Government service, on the basis that the maximum pensi