Shipping has been slow to take on new technologies which help to reduce emissions. Although many new features are available to make ships more fuel efficient, they do not work well if they are retro-fitted. Shipowners are reluctant to use technology unless they have seen it working in other ships; they do not wish to invest their money when they are sceptical about the benefits. At the recent Waterfront Conference on reducing Air Pollution, there were calls for regulation as the only way to force shipbuilders to use green technologies.