Ships entering the waters of Canada and the United States soon will have to use cleaner-burning fuel for their engines in order to cut down on the air pollution they produce in North America. Pushed by the American and Canadian governments, the International Maritime Organization’s Marine Environment Protection Committee approved Emission Control Area rules requiring large ships, including tankers, container ships and cruise vessels, to stop relying on cheap bunker fuel when traveling within 230 miles of the two countries. The United States already imposed standards on its own ships, but an estimated 88% of ships that enter U.S. ports are registered in other countries.