Environment ministers from around the world flew in to Mexico yesterday for the final days of the climate-change talks in Cancun, which threatened to fracture over Chinese-led demands for concessions from the West. Campaigners marched in London yesterday to demand action. As a sign of the work still to be done, only 170 words out of 1,300 on two pages of a key text were undisputed on the "shared vision" of what delegates hoped to accomplish. However, a further issue is now being cited as a significant obstacle in the fight against climate change—corruption.