“In the present case, no doubt the UPSC had resorted to an objective and rational criteria of short-listing but the advertisement does not mention that the two-year experience must be after getting the MSc degree in Agriculture. Hence, we cannot add words to the advertisement and we must read it as it is because an executive agency must be rigorously held to the standards by which it professes its actions to be judged. This rule does not merely rest on Article 14, which requires fairness and non-arbitrariness in executive action, but has an independent existence as a rule of administrative law which has been judicially evolved as a check against exercise of arbitrary power by the executive authority,” the Bench observed.