The oldest oil refinery in India is at

The correct answer is Digboi (in Assam) . Digboi oil refinery was established by Assam Oil Company Limited at Digboi on 11th Dec 1901 . It is Asia's oldest and l ongest operating oil refinery . Key Points The installed capacity at Digboi oil refinery was 0.50 million metric tons per annum but production capacity was enhanced at about 0.65 million metric tons per year. The refinery also has a wax-making unit from crude oil. This refinery has been improved over time and several steps have been taken to improve it. The historic Digboi Refinery is also called the "Gangotri of the Indian Hydrocarbon Sector" .