Reliance Industries Ltd has resumed work at a crude distillation unit at its old Jamnagar refinery after a three-week shut-down because of maintenance.
The company restarted CDU-I on Thursday, an industry source said.
The RIL spokesperson declined comment.
Earlier this month the company had said it would partially shut down the refinery (J-1) for 2-3 weeks to carry out maintenance work.
RIL will shut a crude distillation unit at J-1 of 25,000 barrels per day, from July 3, it had said.
The CDU is the main processing unit in a refinery, which converts crude oil into products.
The company had said it would utilise the shutdown period as an opportunity for implementing significant efficiency improvement measures in the unit.