Oil refineries in India.
After discovery of oil in the Assam state of India in late 1880s, the first oil refinery was set up at Digboi. Digboi Refinery was commissioned in 1901. Following is a list of oil refineries in India, per the Petroleum Planning and Analysis Cell of the Ministry of Petroleum and Natural Gas, Government of India, arranged in decreasing order of their capacity.
As a group, Indian Oil Corporation has the largest refining capacity, with nine refineries located across western, northern and north-eastern regions of India. The Jamnagar Refinery by Reliance Industries Limited is the largest refinery in the world and has the largest Nelson Complexity Index in India of 21.1. Various refineries are undergoing capacity expansions, and the Barmer Refinery was expected to be commissioned in January 2024. 
References.
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