(2015-09-26)China plans to start its national emission trading system in 2017, says a China-U.S. joint presidential state on climate change released Friday.

The system is to cover key industry sectors such as iron and steel, power generation, chemicals, building materials, paper-making, and nonferrous metals, according to the document, an outcome of Chinese President Xi Jinping's state visit to the United States.

China also vows to increase the share of green buildings to 50 percent in newly built buildings in cities and towns by 2020 and the share of public transport in motorized travel to 30 percent in big- and medium-sized cities by 2020.