"10. Questions relating to the constitution, pattern, nomenclature of posts, cadres, categories, their creation/abolition, prescription of qualifications and other conditions of service including avenues of promotions and criteria to be fulfilled for such promotions pertain to the field of policy is within the exclusive discretion and jurisdiction of the State, subject, of course, to the limitations or restrictions envisaged in the Constitution of India and it is not for the statutory tribunals, at any rate, to direct the Government to have a particular method of recruitment or eligibility criteria or avenues of promotion or impose itself by substituting its views for that of the State. Similarly, it is well open and within the competency of the State to change the rules relating to a service and alter or amend and vary by addition/substraction the qualifications, eligibility criteria and other conditions of service including avenues of promotion, from time to time, as the administrative exigencies may need or necessitate. Likewise, the State by appropriate rules is entitled to amalgamate departments or bifurcate departments into more and constitute different categories of posts or cadres by undertaking further classification, bifurcation or amalgamation as well as reconstitute and restructure the pattern and cadres/categories of service, as may be required from time to time by abolishing the existing cadres/posts and creating new cadres/posts. There is no right in any employee of the State to claim that rules governing conditions of his service should be forever the same as the one when he entered service for all purposes and except for ensuring or safeguarding rights or benefits already earned, acquired or accrued at a particular point of time, a government servant has no right to challenge the authority of the State to amend, alter and bring into force new rules relating to even an existing service."