United Press International: China says a proposed carbon tax on imported goods from countries without stringent environmental laws would violate World Trade Organization rules. Expressing his government’s firm opposition to any such tax, Chinese Assistant Finance Minister Zhu Guangyao said it would amount to trade protectionism, China Daily reported. The carbon tax as it relates to climate change is expected to figure at the Group of 20 Summit next week in Pittsburgh. Referring to a bill passed by …