Summarize the following court judgment. vil Appeal Nos. 2270 73 of 1987 & 17 13/1990. From the Judgment & Order dated the 11.8.1978 of the Karnataka High Court in Writ Petition No. 4609/76	 4610/76 & 4611 of 1976. P.P. Rao and S.R. Bhatt for the Appellants. M. Veerappa for the Respondents. The Judgment of the Court was delivered by SINGH	 J. Special leave granted. These appeals are directed against the judgment of a Division Bench of the High Court of Karnataka dated August 11	 1978 dismissing the appellants ' writ petition under Article 226 of the Constitution of India challenging validi ty of the revised select list prepared by the Karnataka Public Service Commission for appointment to the posts of Tehsildars. In the State of Karnataka recruitment to the posts of Tehsildars is regulated by the Karnataka Administrative Services (Tehsildars) Recruitment (Special) Rules 1975 (hereinafter referred to as 1975 Rules). The Karnataka Public Service Commission (hereinafter referred to as the Commission) issued a Notification on May 23	 1975 (published on May 29	 1975) inviting applications from in service candidates for recruitment to 50 posts of Tehsildars. Para graph 3 of the Notification specified details of the posts reserved for candidates belonging to Scheduled Castes	 Scheduled Tribes and other Backward classes including 10% of posts set apart for Ex Military Personnel. According to the figures specified	 therein	 out of 50 posts of 243 Tehsildars	 5 posts were reserved for Ex Military Personnel	 7 posts for Schedule Castes	 1 post for Schedule Tribes and 13 posts for other Backward classes. Paragraph 3 of the advertisement stated that in the event of non availability of sufficient number of candidates belonging to Scheduled Castes. Scheduled Tribes and other Backward classes or Ex Military personnel	 for filing to the reserved vacancies	 such vacancies shall be filled up as per Rules in force. The Notification further gave details of the written and viva voce examinations. Para 14 of the Notification stated that the provisions of 1975 Rules and Rules 7 to 14 of the Karna taka Recruitment of Gazetted Probationers (Class I and II posts Appointment by Competitive Examination) Rules 1966 (hereinafter referred to as 1966 Rules)	 shall mutatis mutandis apply to the conduct of the competitive examination and the provisions of the Karnataka State Civil Services (General Recruitment) Rules 1957 (hereinafter referred to as 1957 Rules) shall apply in respect of matters for which no provision is made in the Rules. Pursuant to the advertisement	 the appellants who were in service of the State Government applied for their selection and appointment to the posts of Tehsildars. After the written examination and viva voce test the Commission finalised the list of successful candidates and published the same in the Karnata ka Gazette dated March 18	 1976. The Commission also noti fied in additional list of successful candidates for ap pointment to the posts of Tehsildars in accordance with 1975 Rules	 which included the names of the appellants. In pre paring the select list and making reservation to the various categories	 the Commission followed the directions and the procedure as contained in the Government Order dated 6th September 1969. The State Government refused to approve the list prepared by the Commission as in its opinion the reser vation for the Scheduled Castes	 Scheduled Tribes and other Backward classes should have been made in accordance with the directions and procedure contained in the Government Order dated 9th July 1975. The State Government by its order dated 23rd April 1976 directed the Commission to prepare a fresh list of successful candidates by making reservations in accordance with the procedure contained in the Government order dated 9th July 1975. Pursuant to the directions of the State Government the Commission prepared the select list afresh	 after making reservations in accordance with the procedure prescribed by the Government Order dated 9th July 1975	 and published the same on 27th May 1976. The appel lants ' names did not figure in the revised list of candi dates. The appellants challenged validity of the Government Order dated 23rd April 1976 as well as the revised list prepared by the Commission and also the validity of the Government Order dated 9th July 1975	 by means of writ petitions before the High Court 244 on a number of grounds. A Division Bench of the High Court by its order dated 11th August 1978 dismissed the petitions. Hence these appeals. The appellants had challenged validity of the Government Order dated 9th July 1975	 prescribing mode for preparing the select list by	 making reservation for Scheduled Castes	 Scheduled Tribes and other Backward classes	 on the ground that the same was inconsistent with the statutory Rule 10 of 1966 Rules and further on the ground that the directions contained therein were violative of Articles 16(1) and 16(4) of the Constitution Of India. The High Court rejected both the contentions holding that the directions contained in the Government Order dated 9th July 1975 were not violative of Rule 10(2) and there was no violation of Article 16 of the Constitution. The High Court upheld the Government Order dated 23rd April 1976 directing the Commission to prepare the select list afresh in accordance with the mode pre scribed under the Government Order dated 9th July 1975. Learned counsel for the appellants did not pursue the chal lenge relating to the validity of the Government Order dated 9th July 1975 before us instead he assailed the validity of the State Government 's Order dated 23rd April 1976 directing the Commission to prepare a revised list in accordance with the Government Order dated 9th July 1975	 on the ground the Government Order was not applicable to the selection. 'Learned counsel for the appellants urged that the Commission had rightly prepared the list of successful candidates published on 18th May 1976 in accordance with the directions contained in the Government Order dated 6th September 1969 by making reservation of posts of Scheduled Castes	 Scheduled Tribes and other Backward classes but the State Government wrongly refused to approve the said list. He urged that the mode of selection and procedure for making reservation as prescribed by the Government Order dated 9th July 1975 was not applicable to the selection as advertise ment had been issued in May 1975	 and the process of selec tion had already commenced prior to the issue of the Govern ment Order dated 9th July 1975. The revised list of success ful candidates prepared by the Commission pursuant to the Government 's directions dated 23rd April 1976 was illegal and contrary to the Rules. Learned counsel for the respond ents submitted that the Government Order dated 9th July 1975 prescribed mode of selection and it also prescribed proce dure for making reservations for Scheduled Castes	 Scheduled Tribes and other Backward classes in supersession of the earlier Government Order including the Government Order dated 6th September 1969 therefore the Commission was 245 found to follow the procedure as prescribed in the aforesaid order in preparing the select list. Since the list of suc cessful candidates had not been prepared in accordance with the Government Order dated 9th July 1975 the State Govern ment was justified in insisting upon the Commission to prepare the list afresh in accordance with the directions contained in the aforesaid Government Order. The question which requires determination is	 which of the two Government Orders	 namely	 6th September 1969 and 9th July 1975	 the Commission was required to be followed in preparing the select list for appointment to the posts of Tehsildars as both the Government Orders contained direc tions for making reservations in preparing the select list. In order to determine the question	 it would be necessary to refer to the directions contained in the two Government Orders. There is no dispute that the recruitment of in service candidates for the 50 posts of Tehsildars in dis pute	 was regulated by the 1975 Rules framed under Article 309 of the Constitution as published in the Gazette on 20th March 1975. Rule 5 laid down that the provisions of Rules 7 to 14 of 1966 Rules shall mutatis mutandis apply to conduct of competitive examination and the provisions of Karnataka State Civil Services (General Recruitment) Rules 1957 shall apply in respect of matters for which no provi sion is made in the Rules. The aforesaid Rules do not pre scribe any procedure for preparation of select list or for making reservations but in view of Rule 5 the provisions of other Rules are made applicable. Rule 10 of the Karnataka Rules 1966 which provides for reservations for Scheduled Castes	 Scheduled Tribes and other Backward classes was applicable in view of Rule 5 of 1975 Rules. Rule 10 of 1966 Rules is as under: "10. Reservation for Scheduled Castes	 Scheduled Tribes and other backward classes (1) There shall be reservation of vacancies for candidates belonging to Scheduled Castes	 Scheduled Tribes and other Backward Classes to the extent provided for by the Government by any general or special orders. (2) In filling the vacancies to reserved	 candi dates who are members of the Scheduled Castes and Scheduled Tribes and other Backward Classes shall be considered for appointment in the order of merit in which their names appear in the list of successful candidates irrespective of their relative rank as compared with other candidates and to services according to the reservation made for them in such services. 246 (3) If a sufficient number of candidates who are members of the Scheduled Castes	 Scheduled Tribes and other backward classes are not available for filling up the vacan cies reserved for them	 such vacancies shall be filled up by the appointment of other candidates in the list. " Pursuant to Clause (1) of Rule 10 of the State Government has been providing for reservation of vacancies in favour of candidates belonging to Scheduled Castes	 Scheduled Tribes and other Backward classes by means of executive orders issued from time to time. The Government Order dated 6th September 1969	 was issued under Rule 10(1) which provided that reservations for appointment to post in the State Civil Service shall continue to be made in favour of Scheduled Tribes	 Scheduled Castes and other Backward classes to the extent of 3%	 15% and 30% respectively	 where the posts are filled up by direct recruitment. Para 5 of the Government Order directed that the Commission and other recruiting authorities shall follow the procedure prescribed in Annex ure 2 to the Government Order in making reservations and preparing list of selected candidates. There is no dispute that the Commission had prepared the select list which was published on 18th March 1976 in accordance with the proce dure laid down in Annexure 2 to the Government Order dated 6th September 1969. During the pendency of selection	 the State Government issued the order dated 9th July 1975 revising the extent of reservation and also prescribing a different mode of selec tion. Para 4 of that Government Order laid down that while making appointment to the State Civil Services	 reservation in favour of Scheduled Castes	 Scheduled Tribes	 Backward Tribes and other Backward classes shall be made to the extent of 15%	 3%	 3% and 28% respectively	 in case of direct recruitment. Para 6 of the Order further directed that in case of direct recruitment where the selection is made by the Public Service Commission or any other recruit ing authority	 the procedure as prescribed in Annexure 2 to the Order shall be followed in preparing the list of select ed candidates. Annexure "to the Order prescribed mode of selection	 which is quite different than that contained in Annexure 2 to the Government Order dated 6th September 1969. It is not necessary to go into the details of the two modes as there is no dispute that the Commission had followed the procedure as prescribed under Annexure .? to the Government. Order dated 6th September 1969 and the list	 so prepared was not approved by the State Government as it was of the opin ion that the Commission should have followed the mode of selection as contained in Annexure 2 to the Government Order dated 247 9th July 1975 in preparing the select list. It appears that the Commission insisted before the State Government that in view of Para II of the Government Order dated 9th July 1975 reservations made in favour of Scheduled Castes	 Scheduled Tribes and other Backward classes already notified before the issue of Government Order dated 9th July 1975 remain unchanged therefore the provisions of the Gov ernment Order dated 6th September 1969 had to be followed both in regard to reservations and the mode of selection. The State Government by its Order dated 23rd April 1976 refused to accept the Commission 's plea and it directed the Commission to prepare a revised list in accordance with the provisions of Government Order dated 9th July 1975. The State Government while rejecting the Commission 's plea and issuing the aforesaid direction made observations as under: "Para 11 of the G.O. dated 9th July 1975 supersedes a11 the previous Government Orders cited in the preamble to that order	 including the G.O. dated 6th September 1969. The same para states that the order	 came into force with immediate effect	 but makes only one exception i.e. in the matter of reservations already made in the cases of posts and serv ices	 for which advertisement had been issued prior to the coming into force of the G.O. dated 9th July 1975. This means that except in the matter of reservations made in posts for which applications had already been called for	 in all other matters the provisions of the G.O. dated 9th July 1975 would apply. The words are clear that the intention is also clearly spelt out. Hence so far as the mode of selec tion is concerned	 the one prescribed in Annexure II to the G.O. dated 9th July 1975 will have to be followed in respect of all selections made after that date either a literal construction or a harmonious construction of the various clauses of the G.O. dated 9th July 1975 leads to the above conclusion. For these reasons the Commission 's view that in respect of posts already advertised prior to the issue of the Government Order dated 9th July 1975	 the mode of selec tion prescribed in the earlier Government Orders and to be followed is not acceptable to Government. " In our opinion the State Government 's view was contrary to the directions contained in para 11 of its Order dated 9th July 1975	 which is as under: 248 1. This Government Order supersedes the Government Order cited in the preamble and shall come into force with immediate effect	 subject to the provision that the reserva tion already made for any category of posts or service and advertised before the issue of this Government Order shall remain unchanged and shall be deemed to have been validly made. All official memoranda	 Circulars and instructions issued in pursuance of the Government Orders superseded by this Government Order shall also be deemed to have been superseded if such instructions are contrary to the provi sions of this Government Order." (emphasis supplied). Indisputably the aforesaid Government Order superseded all earlier Government Orders on the subject including the Government Order dated 6th September 1969 but while super seding those orders provision was made in para 11 to save the selection which was pending. Para 11 clearly stated that though earlier Government Orders laying down percentage of reservation required to be made in favour of Scheduled Castes	 Scheduled Tribes and other Backward classes includ ing the mode of selection in preparing the select list	 stood superseded	 but it saved the reservations made for any category of post or service in respect of which advertise ment had already been issued before the issue of the Govern ment Order dated 9th July 1975. This follows from the ex pression "reservations already made for any category of posts or service and advertised before the issue of this Government Order shall be deemed to have been validly made". These directions stipulated that where reservations were already made and advertisement had been issued	 and the selection was pending on 9th July 1975	 the same shall remain unaffected and the selection shall be made in accord ance with the earlier Government Orders	 and the same shall be treated to have been made validly. Para 11 is in the nature of a saving clause	 its object and purpose	 was to save the selections in respect of which proceedings had already been initiated by issuing advertisement. In view of the Government 's own directions	 as contained in para 11 of its Order the amended mode of selection was not applicable therefore the Commission rightly followed the mode of the selection prescribed under the Government Order dated 6th September 1969 as admittedly the said Order was in force prior to 9th July 1975. The State Government 's interpretation of para 11 of its Order dated 9th July 1975 was incorrect and wrong. It failed to appreciate that in the instant case reservations. had already been made and 249 notified under the advertisement published on 18th May 1975. Therefore the conditions precedent contemplated in para 11 were fully satisfied. In this view the selection made by the commission by following the reservations and the mode of selection as prescribed under the provisions of the Govern ment Order dated 6th September 1969 were deemed to have been made validly in accordance with the provisions of para 11 of the Government Order. It is relevant to point out that the Government Orders dated 6th September 1969 and 9th July 1975 both had been issued by the Government in exercise of its statutory power under Rule 10 of 1975 Rules	 making provi sions for reservations and prescribing mode of selection. A Government Order issued in exercise of statutory powers acquires statutory force	 therefore	 the provisions con tained in the aforesaid Government Orders including the provisions of para 11 of the Government Order dated 9th July 1975 also acquired statutory character. Though para 11 superseded earlier Government Orders but it expressly saved the pending selections where reservations were already made and advertisement had been issued. Para 11 being statutory in nature was binding on the Government and the Government had no authority to direct the Commission by means of Admin istrative Order to revise the Select List in accordance with the amended mode of selection as prescribed under the Gov ernment 's Order dated 9th July 1975. In our opinion the State Government was bound to give full effect to the provi sions of Para 11 of the Government Order dated 9th July 1975 and therefore directions contained in its order dated 23rd April 1976 were illegal. There is yet another aspect of the question. Where advertisement is issued inviting applications for direct recruitment to a category of posts	 and the advertisement expressly states that selection shall be made in accordance with the existing Rules or Government Orders	 and if it further indicates the extent of reservations in favour of various categories	 the selection of candidates in such a case must be made in accordance with the then existing Rules and Government Orders. Candidates who apply	 and undergo written or viva voce test acquire vested right for being considered for selections in accordance with the terms and conditions contained in the advertisement	 unless the adver tisement itself indicates a contrary intention. Generally	 a candidate has right to be considered in accordance with the terms and conditions set out in the advertisement as his right crystalises on the date of publication of advertise ment	 however he has no absolute right in the matter. If the recruitment Rules are amended retrospectively during the pendency of selection	 in that event selection must be held in accordance with the amended Rules. Whether the Rules have 238 retrospective effect or not	 primarily depends upon the language of the Rules and its construction to ascertain the legislative intent. The legislative intent is ascertained either by express provision or by necessary implication	 if the amended Rules are not retrospective in nature the selec tion must be regulated in accordance with the Rules and orders which were in force on the date of advertisement. Determination of this question largely depends on the facts of each case having regard to the terms and conditions set out in the advertisement and the relevant Rules and orders. Lest there be any confusion	 we would like to make it clear that a candidate on making application for a post pursuant to an advertisement does not acquire any vested right for selection	 but if he is eligible and is otherwise qualified in accordance with the relevant Rules and the terms con tained in the advertisement	 he does acquire a vested right for being considered for selection in accordance with the Rules as they existed on the date of advertisement. He cannot be deprived of that limited right on the amendment of Rules during the pendency of selection unless the amended Rules are retrospective in nature. In B.N. Nagarajan & Ors. vs State of Mysore & Ors. 	 	 the dispute related to the validity of appointment of Assistant Engineers. The Public Service Commission invited applications by issuing Notifications for appointment to the post of Assistant Engineers in October 1958	 May 1959 and April 1960. The Commission made selec tion	 interviewed the candidates and sent the select list to the Government in October/November 1960. But before the appointment could be made the Mysore Public Works	 Engineer ing Department Services (Recruitment) Rules 1960 came into force which prescribed different provisions than those prescribed in the earlier Notifications in pursuance whereof the Public Service Commission had made the selections. The validity of the appointment made by the Government on the basis of the selection made by the Commission was chal lenged. The High Court quashed the selection and appoint ments made in pursuance thereof. On appeal before this Court	 validity of the appointment were assailed on the ground that since the appointments had been made after the amendment of the Rules the appointments should have been made in accordance with the amended Rules. A Constitution Bench of this Court rejected the contention holding that since the whole procedure of issuing advertisement	 holding interviews and recommending the names having been followed in accordance with the then existing Rules prior to the enforcement of the amended Rules the appointments made on the basis of the recommendation made by the Public Service Commission could not be rendered invalid. 250 In Y.V. Rangaiah J. Sreenivasa Rao	 similar Question arose relating to recruitment by promotion. The question was whether promotion should be made in accord ance with the Rules	 in force on the date the vacancies occurred or in accordance with the amended Rules. The Court observed as under: "The vacancies which occurred prior to the amended rules would be governed by the old rules and not by the amended rules. It is admitted by counsel for both the parties that henceforth promotion to the post of Sub Registrar Grade II will be according to the new rules on the zonal basis and not on the Statewise basis and	 therefore	 there was no question of challenging the new rules. But the question is of filling the vacancies that occurred prior to the amended rules. We have not the slightest doubt that the posts which fell vacant prior to the amended rules would be governed by the old rules and not by the new rules. " The same view was taken in P. Ganeshwar Rao & Ors. vs State of Andhra Pradesh & Ors.	 [1988] Supp. SCC 740. Similar view was taken in A.A. Calton vs Director of Education & Ors.	 [ 1983] 3SCC 33. It is a well accepted principle of construc tion that a statutory rule or Government Order is prospec tive in nature unless it is expressly or by necessary impli cation made to have retrospective effect. Where proceedings are initiated for selection by issuing advertisement	 the selection should normally be regulated by the then existing rules and Government Orders and any amendment of the rules or the Government Order pending the selection should not affect the validity of the selection made by the selecting authority or the Public Service Commission unless the amend ed rules or the amended Government orders issued in exercise of its statutory power either by express provision or by necessary intendment indicate that amended Rules shall be applicable to the pending selections. See P. Mahendra & Ors. vs State of Karnataka & Ors. 	 [1989] 4 Judgment Today SC 459. In the instant case	 para 11 of the Government Order dated 9th July 1975 made the Government 's intention clear that the revised directions which were contained in that Government Order would not apply to the selections in re spect of which advertisement had already been issued	 there fore the mode of selection as contained in Annexure 2 to the Government Order dated 9th July 1975 was not applicable to the selection for filling the 50 posts of Tehsildars pending before the Public Service Commission. We are	 therefore	 of the opinion that the 251 select list including the additional list as prepared by the commission and published in March 1976 was legal and valid and though Government wrongly refused to approve the same. The State Government 's Order dated 23rd April 1976 directing the Commission to prepare fresh list in accordance with the mode of selection as contained in Annexure 2 to the Govern ment Order dated 9th July 1975 was illegal consequently the select list prepared afresh by the Commission pursuant to the directions of the State Government is not sustainable in law. Since the additional list prepared by the Commission contained the names of the appellants	 they were entitled to appointment to posts of Tehsildars. We accordingly allow the appeals set aside the order of the High Court and direct the State Government to appoint the appellants to the posts of Tehsildars	 on the basis of additional list published by the Commission on 18th March 1976. During the pendency of the writ petition before the High Court	 appointments were made to the posts of Tehsildars on the basis of the revised list prepared by the Commission in accordance with the directions of the State Government dated 23rd April 1976. Pursuant to the interim direction of the High Court the appointment orders contained a specific term that the appointments would be subject to the result of the writ petition filed by the appellants. Since the appellants have succeeded	 the respondents ' appointment is liable to be set aside. The respondents have been working for a period of about 14 years	 it would cause great hardship to them if their appointment is quashed	 and they are directed to vacate the office which they have been holding during all these years. At the same time the appellants have been wrongly denied their right to the posts of Tehsildars. Having regard to these facts and circumstances	 we are of the opinion that it would be expedient in the interest of justice not to interfere with the respondents ' appointment but at the same time steps should be taken to enforce the appellants ' right to the posts of Tehsildars. In this view	 we direct the State Government to appoint the appellants on the posts of Tehsildars with retrospective effect	 but if no vacancies are available the State Government will create supernumerary posts of Tehsildars for appointing the appel lants against those posts. We further direct that for pur pose of seniority the appellants should be placed below the last candidate appointed in 1976	 but they will not be entitled to any back wages. The appellants will be entitled to promotion if otherwise found suitable. In the circumstances of the 	case	 parties shall bear their own costs. S.B. Appeals allowed.

The Karnataka Public Service Commission issued a notifi cation on 23rd May 1975 inviting applications from in serv ice candidates for recruitment to 50 posts of Tehsildars. In para 14 of the notification it was stated that provisions of 1975 Rules	 and Rules 7 to 14 of the Karnataka Recruitment of Gazetted Probationers (Class I & 11 posts Appointment by Competitive Examination) Rules	 1966 shall mutatis mutandis apply to the conduct of the competitive Examination and the provisions of the Karnataka State Civil Services (General Recruitment) Rules	 1957 shall apply in respect of matters for which no provision is made in the Rules. In preparing the select list and making reservations to the various categories	 the Commission followed the direc tions and the procedure as contained in Government Order dated 6th September 1969. The State Government refused to approve the list and directed the Commission on 23.4.76 to prepare the list afresh following the Government Order dated 7th July 1975. The Commission thereupon prepared the list afresh as per Government Order of 7th July 1975. In the revised list	 the appellants names did not figure. The appellants challenged the validity of the Government Order dated 23rd April 1976 as well as the revised list and the validity of the Government Order dated 9th July 1975 by means of writ petitions before the High Court on a number of grounds. The appellants contended that the Government Order dated 7th July 1975 prescribing mode of preparing the select list by making reservations for various categories was inconsistent with the statutory Rule 10 of 1966 Rules	 and further the directions contained therein were violative of Articles 16(1) and 16(4) of the Constitution of India. 240 The High Court rejected both the contentions holding that the directions contained in Government Order of 9th July 1975 were not violative of Rule 10(2) and there was no violation of Article 16 of the Constitution. The High Court also upheld the Government Order dated 23.4.76 directing the Commission to prepare the select list afresh in accordance with the mode prescribed vide Government Order of 9th July 1975. In this Court	 the appellants did not pursue their challenge to the validity of the Government Order dated 9.7.75 but they assailed the validity of Government Order dated 23.4.76 wherein the Government directed the Commission to prepare a revised list in accordance with the Government Order dated 9.7.75 on the ground that the Government Order was not applicable to the pending selection. The appellants also urged that the mode of selection and procedure for making reservations as prescribed by Govern ment Order of 9th July 1975 was not applicable to the selec tion as advertisement had been issued in May 1975 and the process of selection had already commenced prior to the issue of Government Order dated 9th July 1975	 and that the revised list of successful candidates prepared by the com mission as per Government directions of 23.4.76 was illegal and contrary to the Rules. On behalf of the Respondents it was submitted that the list of successful candidates had been prepared in accord ance with Government Order dated 9th July 1975	 the State Government was justified in insisting upon the Commission to prepare the list afresh in accordance with the directions contained in the aforesaid order. Allowing the Appeals and setting aside the Order of the High Court	 HELD: (1) Where advertisement is issued inviting appli cations for direct recruitment to a category of posts and the advertisement expressly states that selection shall be made in accordance with the existing rules or Government Orders and if it further indicated the extent of reserva tions in favour of various categories	 the selection of candidates in such a case must be made in accordance with the then existing Rules and Government Orders if any. (2) Whether the Rules have retrospective effect or not primarily depends upon the language of the Rules and its construction to ascertain the legislative intent. 241 (3) Indisputably the Government Order of 9th July 1975 superseded all earlier Government Orders including that of 6th September 1969 but in para II it saved the selection which was pending i.e. it saved the reservations already made for any category of post or service in respect of which advertisement had already been issued before the issue of Government Order dated 9th July 1975. Para II was in the nature of a saving clause	 and the Commission rightly fol lowed the mode of selection prescribed under the Government Order in force prior to Government Order of 9th July 1975. The State Government was bound to give full effect to the provisions of para II of Government Order dated 9th July 1975. therefore directions contained in its order dated 23.4.76 were illegal [248C E; 249E] 4. Another aspect of the instant case is that where advertisement is issued for direct recruitment to a category of posts expressly stating that selection shall be made in accordance with the existing rules or Government Orders and also indicates the extent of reservations in favour of various categories	 the selection of candidates must be made in accordance with these rules and Government Order. The candidates who applied for selection in pursuance of the advertisement	 acquired vested right for being considered for selection in accordance with the terms and conditions of the advertisement. [249E G] 5. In case the recruitment Rules are amended retrospec tively during the pendency of the selection then selection has to be made in accordance with the amended rules. Whether rules have retrospective effect or not primarily depends upon the language of the Rules and its construction to ascertain the legislative intent	 either by express provi sion or by necessary implication. If the amended Rules are not retrospective in nature the selection must be regulated in accordance with the existing Rules and orders in force at the time of advertisement. [249H; 250A B] (6) It is a well accepted principle of construction that Statutory Rule or Government Order is prospective in nature unless it is expressly or by necessary implication made to have retrospective effect. [251 D] (7) In the instant case	 para II of the Government Order dated 9th July 1975 made the Governments intention clear that the revised directions which are contained in the said Government Order would not apply to the selection in respect of which advertisement had already been issued. Therefore the mode of selection as contained in Annexure to the Gov ernment Order dated 9th July 1975 was not applicable to the selection for filling 50 posts of Tehsildars pending before the Public Service Commission. [251G H] 242 8. Having regard to the facts the circumstances of the case. it would be expedient in the interest of justice not to interfere with the respondents ' appointment but the State Government is directed to appoint I the appellants on the posts of Tehsildars with retrospective effect. If no vacan cies are available the State Government is directed to create supernumerary posts of Tehsildars for appointing the appellants against those posts. For purposes	 of seniority the appellants should be placed below the last candidate appointed in 1976 but they will not be entitled to any back wages. [252F G]