Oil India Limited is a central public sector undertaking engaged in the business of exploration, development and production of crude oil and natural gas, transportation of crude oil and production of liquid petroleum gas. The central public sector undertaking is a Maharatna, with the Ministry of Petroleum and Natural Gas overseeing its operations. Headquartered in Duliajan, Assam, the company has its offices in Duliajan, Noida, Kolkata, Guwahati and Jodhpur. The company's history spans the discovery of crude oil in India in the year 1889, this was second in the World in the far east of India at Digboi and Naharkatiya, Assam to its present status as a fully integrated upstream petroleum company presently operating in more than 9 locations overseas. Recently, OIL acquired majority shares in Numaligarh Refinery Limited from Bharat Petroleum Corporation Limited, thus making Numaligarh Refinery Limited a subsidiary of OIL. State run oil major Oil India Limited was elevated as to the Maharatna status on recommendation from the Finance ministry of India government. This makes Oil India Limited the 13th Maharatna Central Public Sector Enterprises. Wikipedia