Where is India's oldest and first successful oil field located?

The correct answer is Digboi, Assam . Key Points Digboi is historically significant as the site of the first commercial oil discovery in India and is often referred to as the Oil City of Assam . The drilling for oil at Digboi commenced in 1889 , making it the oldest operational oil field in Asia and one of the oldest in the world. Oil was successfully struck at a depth of 178 feet on November 19, 1889 , by the Assam Railways and Trading Company . To manage the production and refining process, the Assam Oil Company was established in 1899 , leading to the commissioning of the Digboi Refinery in 1901 . The Digboi Oil Field marked the beginning of the organized petroleum industry in the Indian subcontinent, preceding discoveries in other major basins by several decades. Additional Information Mumbai High : Located in the Arabian Sea , approximately 160 km off the coast of Mumbai . It was discovered in 1974 and started production in 1976 ; while it is India's largest oil field , it is much younger than Digboi. Ankleshwar, Gujarat : This onshore field was discovered in 1958 and is part of the Cambay Basin . It was the first major oil find in Western India post-independence. KG Basin : The Krishna-Godavari Basin is located on the East Coast of India. It is renowned for its vast natural gas reserves and deep-water oil discoveries made in the early 2000s .