Hindustan Petroleum Corporation Ltd (HPCL) will stop buying diesel from companies like Reliance Industries Ltd and Nayara Energy once it completes expansion of its Visakhapatnam refinery in Andhra Pradesh and builds a new one in Rajasthan next financial year, company officials said. HPCL owns almost a quarter of petrol pumps in the country but does not have commensurate oil refining capacity to produce petrol and diesel. So to make up for this, it buys products from refiners such as Mangalore Refinery and Petrochemicals Ltd (MRPL), Reliance Industries’ Jamanagar units in Gujarat and Nayara’s Vadinar refinery.