Volkswagen is facing fresh questions about its operations in Xinjiang, after an executive visited the northwestern Chinese region to try to allay concerns that Uyghurs and other Turkic Muslims are subject to forced labor and other abuses under harsh government assimilation policies. The German carmaker’s China chief said he saw no human rights violations at the 10-year-old Urumqi plant, while the company has said that forced labor of Uyghurs is not part of its supply chain.