Iran will invest about ₹1,500 crore to expand a refinery run by Chennai Petroleum in Tamil Nadu's Nagapattinam, the company's Managing Director SN Pandey said. The company is planning to invest ₹27,500 crore to boost the plant's capacity by nine-fold to process 9 million tons annually. Iran holds a 15.4% stake in Chennai Petroleum, while Indian Oil has 51.9% share.