The Urban Air Cleaner UAC-20, a.k.a. “Super Tree,” is busy sucking up fumes in lovely downtown Surquillo What is it with Surquillo, lately? The working-class Lima district is making headlines for advocating innovative, sometimes radical solutions to urban problems.  First Surquillo’s mayor Gustavo Sierra raised eyebrows around the world when he suggested that Peru solve its drug problem by legalizing illicit drugs and handling them through the national health ministry. (Sierra later claimed that he was misquoted and that he does not want to legalize drugs, but, rather, he wants the Peruvian government to fund programs to treat drug addicts. Read his refutation in Spanish here.) Now Surquillo is tackling the less-controversial problem of air pollution by installing a state-of-the-art air purifier nicknamed…