Oil and Natural Gas Corporation. Oil and Natural Gas Corporation (ONGC) is an Indian multinational oil and gas company earlier headquartered in Dehradun, Uttarakhand, India.It is a Public Sector Undertaking (PSU) of the Government of India, under the administrative control of the Ministry of Petroleum and Natural Gas. It is India's largest oil and gas exploration and production company. It produces around 70% of India's crude oil (equivalent to around 30% of the country's total demand) and around 62% of its natural gas.