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In page Chinese national carbon trading scheme:

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In the 2010s, China implemented seven pilot carbon markets in various zones that thrive on production of cement, electricity, heat, petroleum and oil extraction. These zones are: Beijing, Chongqing, Guangdong, Hubei, Shanghai, Shenzhen and Tianjin, which represent 25% of China's total GDP. These stationary activities are known to be the most polluting and largest emitters of GHG.[citation needed] In 2016, it was estimated that 40.24 million metric tons of carbon dioxide have been traded.[2]