The legal judgment clearly establishes that the imposition of customs duty on electricity generated within a Special Economic Zone (SEZ) and supplied to the Domestic Tariff Area (DTA) is not legally sustainable under the current statutory and constitutional framework [p_1][p_86]. The Court's core reasoning is that there is no lawful charging event—such as "import into India"—to justify the levy of customs duty on domestic intra-national transactions of electricity, even when deemed as "imported" under fiction [p_45][p_61].

Furthermore, the Court emphasizes that the authority to impose customs duty is rooted in specific statutory provisions, notably Section 12 of the Customs Act, which applies to goods "imported into India," and Section 30 of the SEZ Act, which treats SEZ-to-DTA transfers as if they were imports for duty purposes, but does not create a new or independent levy [p_40][p_41][p_60][p_62]. The Court finds that the use of notifications labeled as "exemptions" to impose or quantify duties—particularly when such notifications have retrospective effect—is a misapplication of delegated legislative powers, constituting a colourable exercise of authority and thus ultra vires [p_46][p_56].

The Court also reaffirmed that the legal declaration made in a prior judgment, which held that no customs duty could be lawfully imposed on such intra-national electricity transfers, was a binding and comprehensive pronouncement of law, not confined to a particular notification or period. This declaration extended to all transactions on the same legal footing unless there was a material change in the law or facts, neither of which was demonstrated in this case [p_50][p_51][p_88].

Importantly, the Court underscored the principle that once a levy is declared unconstitutional or ultra vires, subsequent notifications that continue to enforce the same levy, even if altered in form or rate, are invalid. The Court rejected the argument that each notification must be separately challenged; it held that the illegality at the root invalidates all derivative measures that seek to enforce the same unlawful levy [p_73][p_75][p_86].

The Court also highlighted the importance of respecting judicial discipline and the doctrine of precedent, emphasizing that a co-ordinate Bench must adhere to the binding effect of earlier authoritative judgments. Any attempt to narrow or sideline a final, binding declaration without proper reference to a larger Bench undermines the rule of law and judicial integrity [p_76][p_79][p_80].

Finally, the Court directed that the authorities must refund the amounts collected under protest during the relevant period, affirming the obligation of the executive to give full effect to judicial pronouncements once they attain finality [p_86][p_89][p_132]. The decision underscores that the absence of a statutory charging provision, combined with the misuse of exemption powers and the violation of constitutional principles, renders the contested levies unlawful, and mandates restitution of the illegally collected amounts.