GUANGZHOU, Sept. 22 (Xinhua) -- Carbon emissions allowances closed at 33.13 yuan (about 4.66 U.S. dollars) per tonne on Monday, remained unchanged from Friday at Guangzhou Emissions Exchange, the largest local carbon market in China.

A total of 2 tonnes of allowances were transacted on Monday with a turnover of 63.7 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 more than 231.9 million tonnes of GDEA, with a total turnover of about 6.74 billion yuan.