China is planning to tighten its control over rare earth metals, the New York Times reported. The country currently accounts for 93% of the world’s production of such metals. China produces 99% of the world’s dysprosium and terbium, elements used for production of green energy technology, including the engines of Toyota’s Prius hybrid cars, and for military hardware such as missiles. The Ministry of Industry and Information Technology has a six-year plan to tighten its control over and limit the exports of the elements, to ensure that Beijing has enough supply for its own needs first. This will likely force many companies to manufacture their products in China in order to have access to the materials. Officials will likely be called to explain the policy at a conference in Beijing on Thursday. Their response could influence whether the Australian government approves two Chinese state-owned mining companies applications to purchase a 51.7% stake in Lynas Corporation and a 25% in Arafura Resources. The two companies are planning to open rare earth mines in Australia with a total output equal to 25% of the world’s current total production.