The Commissioner of CGST and Central Excise, Dibrugarh appealed before the Gauhati High Court against orders of the CESTAT (Kolkata) which had allowed refund claims by Oil India Limited and ONGC for Education Cess (EC) and Secondary and Higher Education Cess (SHEC) paid by mistake on Oil Industry Development (OID) Cess. The core dispute was whether the one-year limitation period under Section 11B of the Central Excise Act, 1944 barred these refund claims, and whether the statutory presumption of unjust enrichment under that section had been properly addressed. The CESTAT had held, relying on decisions of several High Courts including the Gujarat High Court in ONGC Ltd. v. Union of India (2017), that since OID Cess is not a duty of excise, the EC and SHEC paid thereon were amounts paid under a mistake of law, making Section 11B inapplicable and the general limitation provisions of the Limitation Act, 1963 (particularly Section 17) applicable instead. The Gauhati High Court was seized of two substantial questions of law: applicability of the Section 11B time-bar to payments made under a mistake of law, and whether the CESTAT erred in accepting a CA certificate without substantive evidence on unjust enrichment. The judgment text as provided does not record a final operative conclusion, as the order appears to be truncated.