Dr. Joan Clos, who was mayor of Barcelona from 1996 to 2007 and is a medical doctor, became the new executive director of United Nations Human Settlement Program (UN-Habitat) in October, where he works from the Nairobi headquarters. His agency’s mission is to ensure safe, sustainable housing for people in urban areas, and in his new capacity, Dr. Clos said that he would focus on improving the conditions of the nearly 1 billion people who reside in slums, while also striving to make cities greener. This interview was conducted by e-mail with Dr. Clos in December and has been edited and condensed from the original exchange.

Since the Group of 20’s first formal meeting in 2008, its relationship with the United Nations has been noticeably cool. As a result, some at the UN have gone so far as to call the G-20 illegitimate, viewing it as a threat to the UN’s international prowess.

Though intestinal worms affect 1.2 billion children under age 15, soil-transmitted helminthiasis is labeled a “neglected tropical disease” by the World Health Organization, meaning that it persists in only the poorest regions. With hundreds of millions of free deworming tablets about to be made available each year through the UN agency as well as through Johnson & Johnson and GlaxoSmithKline, the disease could be on its way toward shedding its “neglected” tag.