What do Beijing residents expect of their new mayor? Of all the things that need improving, cleaner air will be at the top of many people's wish list.

Wang Anshun, who was acting mayor before he was elected mayor by the city's legislators on Monday, said on Sunday that doing things in line with the law of economics and the law of social development was the best way to address the conflicts between ever-burgeoning population size, dwindling resources and worsening environment. He also said that Beijing will be governed according to law.

Beijing has a goal of building itself into a world city. What is a world city?