An age-based classification among employees of the same class, without a reasonable nexus to the object of the differentiation, is violative of Articles 14 and 16(1) of the Constitution.

In this application under Article 226 of the Consti­tution of India, the petitioner challenges the provision of age limit contained under proviso (b) to Clause (c) of Sub-rule (1) of Rule 6 of the Assam Taxation Services Rules, 1962 as viol­ative of the provisions of Articles 14 and 16 of the Constitution. The circumstances leading to the present writ petition are as follows. The petitioner Shri Tarinidhar Choudhury was appointed as a Lower Division Assistant in the Office of the Superin­tendent of Taxes, Gauhati in the Assam Taxation Services in 1948, He joined the post on 1.6.48, subsequently he was promoted as an Upper Division Assistant and on 1.10.75 he was promoted to the post of Head Assistant in the unit office of Gauhati. The conditions of service of the employees of Assam Taxation Services are regulated by the provisions of the Assam Taxation Services Rules, 1962 as amended up-to-date (Hencefor­th to be called as the Rules.) Under Rule 3 of the Rules, there a are three classes of services appertaining to Assam Taxation Services, viz., Class-I-Asstt. Commissioner of Taxes, Class-II-Superintendent of Taxes or Agricultural Income-Tax Officers and Class-III-Inspectors of Taxes. Each of these classes constitute a separate cadre.

2. According to Rule 7(1) of the Rules, the Govt. has to prepare a list of officers eligible for promotion (to be called as gradation list) in order of seniority-cum-merit of each cadre and accordingly the Assam Govt. prepared and finalised a grada­tion list of ministerial officers of Assam Taxation Services in-1977 which is still in force. In the aforesaid gradation list, the name of the petitioner stands at SI. No. 2 and names of respondents No. 5 to 17 stand in SI. No. 118, 119, 120, 122, 124, 125, 126, 127, 130, 131, 132, 133 and 135 respectively. Under the provi­sions of Rule 6(1)(c) of the Rules, 25% of the vacancies in Class-III cadre (Inspectors of Taxes) have to be filled up at a time by promotion from the ministerial Govt. servants of the Assam Taxation Services and as such the petitioner's claim to promo­tion fall due immediately after SI. No. 1 of the gradation list.

3. But no consideration of the claim of the petitioner was made and respondents No. 5 to 17 as well as 1, Shri S.K. Rabha (Since deceased) though occupying positions in the gradation list much junior to the position of the petitioner were promoted in March, 1979 as Inspectors of Taxes vide order of the Assam Government No. FEB. 117/77/Pt./75 dated 15.3.79 in exercise of the powers under Rule 6(1)(c) of the Rules. Rule 6 of the Rules which regulates the promotion of employees in the Assam Taxation Service is as follows :-

"6. Promotion-(1) Promotion shall be subject to the follo­wing reservations :-

(a) All vacancies to the Class-I cadre shall be filled by promotion of officers belonging to the Class-II cadre.

(b) Fifty per cent of vacancies to be filled at a time in the Class-II cadre shall be by promotion of mem­bers belonging to the Class-III cadre.

(c) Twenty-five per cent of vacancies to be filled at a time in the Class-III cadre shall be by promotion of ministerial Government servants :

Provided that a ministerial Govt. servant shall for promotion satisfy the following conditions :-

(a) That he has rendered atleast 10 years (subsequ­ently 8 years) of service in the office of the Comm­issioner or any subordinate office, and

(b) That he does not cross the age of 42 years on the first day of January of the year in which his promotion is considered by the Commissioner."

4. The petitioner having not been promoted though occu­pying a senior position in the gradation list, represented to the Government against the supersession and was informed that under proviso (b) to clause (c) of sub-rule (1) of Rule 6, he was dis­qualified due to his having crossed the age of 42 years and that for this he was not promoted. The petitioner, therefore, challenges the impugned rule on the grounds, firstly that by imposing the age limit of 42 y