( 1 ) THE petitioners have moved this writ application against the impugned Memo No. 372-Edn. (B) dated 31st July, 1981 for writ of Mandamus commanding the respondents to cancel and withdraw the offending portion of the said Memo by which the age of retirement has been reduced from 65 years to 60 years, a writ of Certiorari for quashing the relevant portion of the said impugned Memo which had reduced the age of retirement from 65 years to 60 years and also a writ of Prohibition directing the respondents not to make any discrimination in the matter of fixation of the age of retirement amongst the teaching and non-teaching staff. The "offending portion" of the impugned Memo dated 31st July, 1981 as described in paragraph 25 of the writ petition which is the target of attack is a portion of Clause 6 of the said Memo which is quoted as under: -"the teachers in all Government aided educational institutions opting for the revised scales of pay shall retire at 60 years, provided however that who were above 54 years but below 57 years of age on April 1, 1981 shall retire on completion of 62 years of age on March 31, 1989 whichever is earlier, and for such teachers who were above 57 years of age on April 1, 198l retirement will be on completion of 65 years or on March 31, 1987 whichever is earlier, The non-teaching employees of all Government aid institutions shall retire at 60 years of age. "

( 2 ) THE case of the petitioners is, in short, as follows:-Prior to the issue of Memo dated 31st July, 1981 the age of superannuation of the teaching and non-teaching staff of the schools in the State of West Bengal was 60 years and that after attaining of the age of superannuation, there was provisions for extension of service year by year for another period of 5 years on condition that the teacher concerned was mentally alert and physically fit. Under Rule 28 (I) (iii) of the Rules for Management and Recognised Non-Government Institutions (Aided and Unaided), 1969 it was provided that the Managing Committee of a School shall subject to the approval of the Director have the power to extend the service of teachers and other employees beyond the date of superannuation and that Rule 28 (2) and (3) of the said Rules provided the procedure to be followed in case of non-granting of extension of service of the teachers and the employees. It is submitted that under the impugned Memo those who are in service on 31st March, 1981. should exercise option either to retain their existing scale of pay and existing terms and conditions of service or to come under the revised scale of pay together with the revised terms and conditions of service as may be determined by the State Government and that under the revised terms and conditions of service one has to retire after attaining the age of 60 years. The petitioners contended that the classification provided for teaching and non-teaching staff who would be opting for new scale of pay and new terms and conditions are not based on any intelligible differentia and the provision is highly discriminatory. The petitioners cited several cases including the case of petitioner No. 3 to show that this particular petitioner retiring at the age of 65 years would be drawing Rs. 3,67,056/- and that the difference of new scale and the old pay scale will result in a loss of not less than Rs. 1,05,006/ -. It is also stated that in case of college teachers the retirement age was 58 years and 60 years and the same has been increased up to 65 years. It is contended that the determination of the age of retirement at the age of 60 years in respect of teaching and non-teaching staff of both primary and secondary schools is highly arbitrary and not based on any rational basis and a discrimination has been done in the case of school teachers and college teachers in determine the age of retirement.

( 3 ) IT is specifically contended in the writ petition that the impugned Memo changing the age of retirement could not s