SHANGHAI - The first carbon permits in Shanghai traded at 27 yuan ($4.43) on Tuesday, as the financial hub launched China's second such trading platform in a bid to cut its fast-growing greenhouse gas emissions.

Three trades for a total of 9,500 permits for 2013 compliance, known as Shanghai Emissions Allowances (SHEAs), went through in the first half-hour after the market opened. A third carbon market will open in Beijing on Thursday.

China has pledged to reduce its emissions per unit of GDP to 40-45 percent below 2005 levels by 2020.

Bin Hui, vice director at the Shanghai Environment and Energy Exchange, told reporters that State-owned power company Huaneng was one of the companies involved in the Tuesday deals, but gave no further details.

The opening price matched the first trades that went through when the Shenzhen emissions market opened in June, but prices there have since risen to around 60 yuan.

A batch of 4,000 permits for use in 2014 also traded in Shanghai at 26 yuan, and 500 for 2015 changed hands at 25 yuan.

Shanghai's platform caps carbon dioxide emissions from 191 big energy users in the financial center, spanning electricity generation, manufacturing, airlines, harbours and commercial buildings.

Participants get free permits from the government to cover most of their expected emissions. If they exceed those levels they must buy permits in the market from companies that have a surplus, or from offset projects elsewhere in China regulated by the central government.

Ni Qianlong of the Shanghai Development and Reform Commission, which administers the market, told reporters on Tuesday that around 160 million permits had been issued for the platform's first year, although the number may be adjusted later.

The Shanghai government said last week companies that have taken action to reduce their emissions over the 2006 to 2011 period will be given additional permits.

Among the companies participating are leading steel producer Baoshan Iron and Steel and chemical company BASF.

The central government has planned seven regional carbon markets as China steps up efforts to limit its impact on global warming, which scientists say cause rising sea levels, extreme weather events and prolonged droughts.

"China will make efforts to contribute to building an international emissions trading system in the future," Xie Zhenhua, vice director of the National Development and Reform Commission (NDRC) said at the Tuesday launch.