China plans to cut production of rare-earth minerals by 20 percent in an effort to consolidate the industry and aid the environment. New production rules in the country will close a third of China’s 23 mines and half of its smelting companies. The United States, Japan, and the European Union have all complained to the World Trade Organization that China is violating trade rules. Rare earths are 17 minerals that are used in most electronic devices, including smartphones, hybrid cars, and weapons. About one third of the world’s rare earth deposits are in China, but the country controls more than 90 percent of production.