The oldest oil field in India is in _____________.

The correct answer is Digboi, Assam . Key Points The oldest oil field in India is Digboi, Assam . Digboi, Assam:- It is India's oldest operating refinery and one of the oldest operating refineries in the world. It is situated in the Tinsukia district of Assam . The historic Digboi Refinery has been termed as the "Gangotri of the Indian Hydrocarbon sector" . A stretch of Dihing or Burhi Dihing in Eastern Assam’s Dibrugarh district witnessed fire following the spillage of crude oil which was being transported to Digboi refinery . Assam is an ecologically sensitive state, spillage of crude or processed oil in river bodies threatens aquatic life . Additional Information India's important oil fields are: Bombay High Oil Field:- Bombay High (now Mumbai High) field is an offshore oilfield located in the Arabian Sea, approximately 160km west of the Mumbai coast, India. Discovered in 1974, the field commenced production in 1976 and is operated by the Oil and Natural Gas Corporation (ONGC). The oil field consists of two blocks named Mumbai High North (MHN) and Mumbai High South (MHS) . The blocks were divided based on shale barriers, assisting in the independent exploitation of reserves at both sites . Ankleshwar Oil Field:- Ankleshwar oil field is one of the main onshore Cenozoic hydrocarbons bearing anticline of deltaic origin known in the Cambay Basin. It runs into the Gulf of Cambay in approximately ENE-WSW direction .