New York City Mayor Michael Bloomberg recently vowed to promote the use of electric taxis as a way to combat climate change. He spoke with delegates at the C40 conference in Hong Kong as he took leadership of the coalition. C40, founded in 2005, is a coalition of 40 cities, and accounts for about 1 in 12 people in the world. The city governments of 25 members of the coalition have oversight of one million taxis. Bloomberg suggested that cities could agree on common taxi designs and place orders for the vehicles together, though this may be hampered by differences in regulations and safety standards. The mayor believes in the executive powers of city government, such as encouraging the installation of energy-efficient electrical equipment in old buildings through city building codes.