B. P. Singh, J.

These four writ Petitions have been heard together since they involve a common question. CWJC No. 7895 of 1988 was admitted for hearing by a Division Bench of this Court by order dated 1.12.1988. By the same order, the Bench directed that the matter be placed for hearing before a Larger Bench since their Lordships doubted the correctness of the decision of this Court in CWJC No. 2387 of 1988 disposed of on 11.8.1988. By order dated 15.12.1988, it was directed that CWJC No. 5585 of 1988 be placed for hearing along with CWJC No, 7895 of 1988. Similarly by order dated 16.12.1988 CWJC No. 5025 of 1988 was also directed to be heard with CWJC No. 7895 of 1988. Lastly by order dated 23.5.1989, it was directed that CWJC No. 4447 of 1989 be heard with CWJC No. 7895 of 1988. This is how all the four writ petitions have been placed for hearing before this bench.

2. Though the facts of the case are some what different, the common issue involved in all the writ petitions is as to whether it is permissible for a candidate to produce the certificates required to be produced under the advertisement at any time, or whether the Bihar public Service Commission may be Justified in refusing to accept the certificates produced after the date mentioned for production of such certificates in the advertisement inviting applications. The petitioners contended that in view of several orders/decisions of this court, the requisite certificates may be produced at any time, and the requirement in the advertisement of their production on or before the date specified in the advertisement can only be considered to be directory and not mandatory. On the other hand, it is contended on behalf of the State as well as by the Bihar public Service Commission that the cut off dates mentioned in the advertisement are meant to be followed, and if the contention of the petitioners were to be accepted by this court, the process of selection will become an unending process and the Commission will find it difficult to finalise the list of selected candidates who may be recommended for appointment.

3. The representative facts may be taken from CWJC No. 5585 of 1988.

The case of the petitioner is that pursuant to the advertisement No. 93 of 1985 inviting applications from eligible candidates for appointment against 245 posts of Assistant Engineer in different work; departments, the petitioner being eligible, applied on 24.9.1985 Some of the posts were reserved for candidates belonging to backward categories. The advertisement clearly provided that certain number of posts were reserved for scheduled castes/scheduled Tribes, backward class and most backward class categories, female candidates belonging to economically weaker sections, and candidates belonging to non scheduled castes, non scheduled tribes and most backward class whole family income did not exceed the limit prescribed for the purpose of income tax. However, in order to claim benefit of reservation, the candidates claiming such reservation had to produce the necessary caste certificate and annual income certificate issued by the officers mentioned in paragraph B of the advertisement, Namely, the District Magistrate, sub-divisional officer/Project Executive Officer/Assistant Project Executive officer/Circle officer-Block Development Officer District Welfare Officer/Sub Divisional Welfare Officer and Fist class Magistrate authorised to issue such certificates. The certificates issued by the above authorities were required to be submitted with the application filed in response to the advertisement, but the certificates were to be taken as valid only if the same was counter signed and verified by the District Magistrate and produced at the time of interview. It is not disputed that the petitioner furnished a caste certificate issued by the District Welfare Officer, Saran dated 24.9.1985 and an income certificate issued by the S. D. O. Chapra dated 28.9.1985 along with his application and claimed re