Among the many reports of abnormal weather patterns in the Arctic, one piece of news that spread throughout the world in spring 2011 was that the ozone hole above the Arctic Circle had expanded to its largest size ever, with possible consequences on Europe, North America, and Japan. Why did such a significant depletion of the ozone layer occur where it was previously deemed unlikely? What kind of impact did this have on Japan? What is going to happen with the Arctic ozone hole? Dr. Hideaki Nakajima of the National Institute for Environmental Studies has been monitoring ozone over the North and South poles in collaboration with environmental scientists from around the world, answers these questions.