Treatment of non-convertible rupees as convertible foreign exchange enables section 80HHB deduction for foreign project receipts. Section 80HHB requires that consideration for execution of foreign projects be payable in convertible foreign exchange. Receipts of consideration paid in non convertible rupees from bilateral account countries are to be treated as equivalent to consideration received in any other convertible foreign exchange, and thus meet the convertible foreign exchange requirement for the deduction, subject to the other statutory conditions.