Russian oil quality from the Baltic port of Ust-Luga was improving on Thursday but was still not good enough for refiners in Europe, with required standards expected to be reached only by May 11, trading sources said. Oil contamination at the port, with organic chlorides that can destroy refining equipment, was first reported late last month. Russian government officials and pipeline monopoly Transneft had promised to fix the problem by May 6, but the deadline kept being postponed. Russia has been forced to curtail output, adding to global supply shortages. As of Thursday, organic chloride content in Ust-Luga stood at 50-60 parts per million (ppm), still above normal levels of 10 ppm, four trading sources said. It will […]