Petroleum or mineral oil is the next major energy source in India after coal. It provides fuel for heating and lighting, lubricants for machinery and raw materials for a number of manufacturing industries.
Four major oilfields of India are
(i) Mumbai High
(ii) Gujarat — Ankeleshwar and Kalol
(iii) Assam — Digboi, Naharkatiya and Moran
(iv) Rajasthan, Mangala, District Barmer