WASHINGTON—The U.S. Transportation Department on Wednesday said it will limit some flights from Chinese carriers to 40 percent passenger capacity for four weeks after the Chinese government imposed similar limits on four United Airlines flights. China told United on Aug. 6 it was imposing sanctions after it alleged five passengers who traveled from San Francisco to Shanghai tested positive for COVID-19 on July 21. The U.S. order said the department will limit over a four-week period each of four Chinese carriers to 40 percent capacity on a single China-U.S. flight. United Airlines said it was “pleased to see this action by the (Transportation Department) in pursuit of fairness in this important market.” The Chinese embassy in Washington did not immediately comment. The U.S. government says China’s “circuit breaker” policy violates the nations’ air services agreement and “places undue culpability on carriers with respect to travelers that test positive for COVID-19 …