Indian Oil Corp, the country's top refiner, has raised $500 million under the Reserve Bank of India's concessional dollar-rupee swap window for external commercial borrowings, its CFO said on Friday.Here are some more details:* The Indian ‌central bank ⁠had ⁠last month rolled out a discounted forex swap facility for external commercial borrowings by state-run companies to encourage dollar inflows as part of measures to strengthen India's balance of payments. The facility allows firms to lock in FX hedges at below-market rates, ⁠encouraging them ‌to raise overseas loans.* ​The company ​raised the funds via a five-year ⁠long-term external commercial borrowing last week, CFO ​Anuj Jain told reporters after IOC's June ​quarter results. He said the company would consider raising additional funds under the facility, which is open until the end of December.* Indian Oil's borrowings have surged by 200 billion ‌rupees in April-June for selling fuels at below-market rates.* The refiner has enough ​crude ​for 45 days, ⁠Chairman Arvinder Singh Sahney said. He said IOC is prepared to buy oil from Saudi Arabia via a ​longer African route.* The RBI has also rolled out a similar facility to offset the hedging costs for banks that raise three- to five-year deposits from non-resident Indians.