The Directorate of Revenue Intelligence (DRI) has filed an appeal before the Supreme Court challenging an order of the Customs, Excise & Service Tax Appellate Tribunal (CESTAT) quashing a case pertaining to over-invoicing allegations against Maharashtra Eastern Grid Power Transmission (MEGPTCL), a subsidiary of Adani Enterprises (AEL), court filings show. The appeal was filed by DRI on January 2.