China has advised its domestic companies to file applications for a renewal of anti-dumping investigation into a type of synthetic rubber imported from South Korea, Japan and Russia, a step that could lead to extension of five-year duties against the rubber chemical. Unless no applications were received for 60 days from March 7, the anti-dumping duties against styrene-butadiene rubber imported from the three nations would be terminated on Sept. 8 this year, China's commerce ministry said in a statement.