Can the hardship of a few be a ground to invalidate a statute or a rule?

Tamil Nadu Urban Local Bodies Act, 1998 — s.198 — Tamil Nadu Urban Local Bodies Rules, 2023 — r.192A(5) — r.202 — r.205 — r.206 — Constitution of India — Art.14 — Inter-se seniority — Ratio and rotation for promotion — Tamil Nadu Urban Local Bodies Rules, 2023 — r.206 — r.192A(5) — State as a single unit — Held: The State is a single unit for appointment, promotion, reversion, transfer and discharge for all posts in the Tamil Nadu Municipal Service, and the Government may order the rotation in which such posts are filled from the feeder categories. (¶18, 21) Constitution of India — Art.14 — Validity of a rule — Hardship of a few — Held further: There is a presumption of constitutionality and the burden lies on the challenger. Hardship of a few cannot be the basis for determining the validity of a statute or rule, so a ratio fixed to remove inequality in promotion is not infirm. (¶30, 32) Service law — Promotion — Right of consideration — Held further: Promotion per se is not a vested right, but consideration for promotion is a fundamental right, and all promotions must be granted strictly in accordance with the Rules and the policy applicable to the posts. Validity of the Government Order upheld; directions issued. (¶37, 39)