P. BHASKARAN vs UNION OF INDIA .

The Supreme Court upheld the Central Administrative Tribunal's decision regarding the seniority of UDCs, emphasizing that ad hoc promotions do not confer seniority rights. The Court clarified that promotions based on options without adherence to recruitment rules are invalid, and seniority must be determined based on the original appointment dates. The Court affirmed that the appellants, who were appointed earlier, retain their seniority despite the ad hoc promotions granted to juniors, thus dismissing the appeal.