Interest on wrongly availed IGST credit depends on the total electronic ITC balance, not IGST head alone. For calculating interest in cases of wrongly availed IGST credit, the total input tax credit available in the electronic credit ledger across IGST, CGST and SGST heads taken together must be considered. No interest arises if, from wrongful availment until reversal, that combined balance never falls below the wrongly availed amount; interest applies to the extent the combined balance falls short. Compensation cess credit is excluded from the combined balance and cannot be used to offset IGST, CGST or SGST liabilities.