China is expected to exceed the target of decreasing greenhouse gas emissions by 40% to 45% by 2020, said Li Gao, an official in charge of climate change from the National Development and Reform Commission, the 21st Century Business Herald reported.

The establishment of a unified national carbon emissions trading market is the key to controlling greenhouse gas emissions via market mechanisms, said Li. 

From 2011, seven regions including Beijing, Tianjin and Shanghai have started the pilot program in carbon trading.

The programs cover industries of electricity, steel and cement, for a total of about 3,000 companies.

By the end of September, the transaction of emissions trading has added up to 197 million tones of carbon dioxide, equal to 4.5 billion yuan.