"The company has scheduled a turnaround for maintenance of one CDU (crude distillation unit) and one FCCU (fluidised catalytic cracking unit) at the Jamnagar refinery complex for a period of approximately 4 weeks starting the 15h of March 2015," the company said in a statement.
The Jamnagar complex houses two refineries with a combined capacity of 62 million tons per annum, the largest at a single location anywhere in the world.
Besides maintenance work, the shutdown would be used to "carry out necessary modifications to improve and enhance the reliability and performance of the units".