Limitation on interest deduction restricts related party interest deductibility and requires carryforward under specified rules. Restriction disallows deduction of interest paid to non-resident associated enterprises where annual interest exceeds the monetary threshold; third party lender debt is treated as associated enterprise debt if guaranteed or matched by an associated enterprise. 'Excess interest' equals interest above 30% of borrower EBITDA or interest paid to associated enterprises, whichever is less. Disallowed interest can be carried forward and deducted against future business profits subject to the annual allowable limit and an eight year carryforward cap. Specified banking, insurance, IFSC finance companies and notified NBFCs are exempt; definitions for debt, Finance Company and permanent establishment apply.