GUANGZHOU - South China's Guangdong province has started allotting 388 million tonnes of carbon emission quotas to selected enterprises, according to the provincial development and reform commission on Wednesday.

An initial 242 companies from power, iron and steel, petrochemical and cement industries have been included in the quota allocation.

By the end of the year, an online platform for carbon emission quota trading will be officially launched.

Under the trading program, companies which emit more than their fare share of emissions will be able to buy unused quotas on the market from firms which pollute less.

Quotas equivalent to 29 million tonnes of carbon emissions will be auctioned and the base price will be 60 yuan ($9.8) per tonne. The rest of the quotas will be allotted to companies for free.

On Tuesday, Shanghai launched its compulsory carbon trading market, the country's second. South China's Shenzhen city started its market in June.

The National Development and Reform Commission, the country's top economic planner, has also approved pilot carbon emission trading schemes in Beijing, Tianjin, Chongqing, Hubei and Guangdong.

The country has pledged to reduce carbon dioxide emissions by 40 to 45 percent per unit of GDP by 2020, in comparison with 2005.