( 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