In a rare public spat involving two Chinese auto majors, Great Wall Motor criticized BYD on Thursday for using cheaper components to circumvent certain pollution standards. The car manufacturer issued a statement indicating that on April 11, it filed a report with regulators regarding alleged issues found in BYD’s Qin Plus and Song Plus plug-in hybrid electric vehicles (PHEVs) due to the utilization of non-pressurized fuel tanks. Many experts believe that such non-pressurized fuel tanks in PHEVs could result in the release of excessive gasoline fumes. BYD promptly refuted the allegations, saying that the emissions tests had been carried out by a third-party automobile inspection center at the behest of Great Wall but that the tests were invalid as they did not comply with regulatory rules. China’s Ministry of Ecology and Environment has intervened to investigate the matter, but according to a report by Caixin, no progress has been made thus far. [Caixin, in Chinese]