Central China's Hubei Province will launch its carbon trading market on April 2, its emissions exchange said Tuesday, a move that could cap carbon dioxide emissions from nearly 140 of its biggest companies.

The Hubei market will be China's sixth of seven planned regional emissions trading schemes as the country steps up its efforts to limit its impact on climate change.

The seventh exchange will be in Southwest China's Chong?qing, and is also scheduled to go into operation this year.

The launch date will mark the opening of secondary trading for companies covered by the scheme, but the government plans to auction an unknown number of permits ahead of that date although details are yet to be sorted out, Wang Hai, vice general manager at the China Hubei Emissions Exchange, told Reuters.

Hubei will issue around 300 million permits for 2014.