The world market for trading greenhouse gas emissions doubled last year to about $70 billion, according to World Bank figures. China accounts for 73 percent of the clean development mechanism (CDM) projects - a major carbon trading business. Until just a few years ago, the idea of making money from emissions trading would have sounded like madness to most businesspeople in China. But the CDM is changing all that. The deal between Myland Group, a chemical plant based in Jiangsu province, and the World Bank is one example.