Carbon emissions allowances closed at 26.03 yuan (about 3.66 U.S. dollars) per tonne on Wednesday, which kept flat compared with Tuesday, at the China Emissions Exchange (Guangzhou), the largest local carbon market in China.

A total of 6,491 tonnes of allowances were transacted on Wednesday, with a turnover of 168,988.26 yuan.

The allowances, officially known as Guangdong Emissions Allowances (GDEA), are carbon dioxide emissions caps assigned to companies. Firms whose emissions surpass their share must buy extra quotas from authorities or purchase unused quotas on the market from those that cause less pollution.

Since its opening in December 2013, the market has traded 132.97 million tonnes of GDEA, with a total turnover of 2.59 billion yuan.