China's national carbon emissions trading market, the biggest of its kind across the globe, started trading on Friday.

According to the Ministry of Ecology and Environment of China, carbon emissions by the 2,225 power companies covered in the first batch of trading will exceed 4 billion tons per year. 

The scheme is to help China to realize the goal of peaking carbon dioxide emissions by 2030 and achieving carbon neutrality by 2060.

Power companies are for now the only participants of the first batch of trading, but the market will expand in the future, said ZHAO Yingming, minister of ecology and environment.

Under the scheme, companies are assigned quotas for carbon emissions based on their output and industry-specific factors and can sell excess emission allowances to those in need of more pollution quotas.

In 2011, 7 provincial regions including Beijing, Tianjin, Shanghai, and Guangdong first rolled out local carbon emissions trading projects.

Data from the ecology and environment ministry showed that by June, over 480 tons of carbon dioxide equivalence were traded in the 7 regions with a total volume of 11.4 billion yuan.