Yale Environment 360: Photographer Sean Gallagher has lived and worked in China for seven years, visiting nearly all of its provinces as he documents the countrys daunting ecological problems and its widely varied landscapes. In a Yale Environment 360 photo essay, the Beijing-based photojournalist chronicles Chinas widespread water and air pollution, the battle against the desertification that has spread across the country's northern regions, and the threats to the nation's biodiversity. "The current state of many...