ISLAMABAD : Taking action on the shortage of petroleum products in the country, the Oil and Gas Regulatory Authority (OGRA) has served show-cause notice to three companies on Wednesday. According to the OGRA spokesperson, Shell, Attock and Total Parco have been asked to present their explanation over the shortage within 24 hours. It is pertinent to mention here that petroleum prices went through another significant decrease on Sunday after Oil & Gas Regulatory Authority (OGRA) summary for slashing prices was approved. Fuel stations in parts of the country remained shut down over lack of supply from private oil companies amid unprecedented lowering of the petroleum products’ prices On Monday, fuel shortage was witnessed at the stations of the private oil companies in Karachi after supplies were not released from the companies. Even police vans were not provided with the fuel as some areas also reported sale of petrol on higher prices. Long queues of vehicles were witnessed at various petrol pumps in the city. The petroleum retailers have demanded of the government to ensure smooth supply of petrol and diesel to the pumps across the country