（初めに右欄で英語を１つ選び、続いて選択肢から１つを選んでください。やり直すときは、英語を選び直すことから始めてください。右の［単語帳］を参考にすることもできます。）China has officially cited environmental issues as one of the key factors for its recent regulation on the industry, but non-environmental motives have also been imputed to China's rare earth policy.
According to The Economist, "Slashing their exports of rare-earth metals...is all about moving Chinese manufacturers up the supply chain, so they can sell valuable finished goods to the world rather than lowly raw materials." One possible example is the division of General Motors which deals with miniaturized magnet research, which shut down its US office and moved all of its staff to China in 2006.
It was reported, but officially denied, that China instituted an export ban on shipments of rare earth oxides (but not alloys) to Japan on 22 September 2010, in response to the detainment of a Chinese fishing boat captain by the Japanese Coast Guard. On September 2, 2010, a few days before the fishing boat incident, The Economist reported that "China...in July announced the latest in a series of annual export reductions, this time by 40% to precisely 30,258 tonnes."
The United States Department of Energy in its 2010 Critical Materials Strategy report identified dysprosium as the element that was most critical in terms of import reliance.