Section 146(2) in The Delhi School Education Rules, 1973
(2)An admission fee of Rs. 3/- per student shall be charged and collected by the aided school for admission to any class in the [Secondary or Senior Secondary stages] [Substituted by the Delhi School Education (Amendment) Rules, 1990 w.e.f. 23.2.1990).] but where a student has already paid an admission fee, no admission fee shall be charged on his promotion to any higher class in the same school; but if he joins any other aided school that other school may charge and collect admission fee from him.