The third line of the China-Central Asia Natural Gas Pipeline started to transport natural gas to China, China National Petroleum Corporation (CNPC) announced late Sunday.

The 1,830-km Line C of the pipeline, parallel to Line A and Line B, starts at the Turkmen-Uzbek border and runs through central Uzbekistan and southern Kazakhstan before reaching China's northwest region of Xinjiang.

The transport capacity of Line C, which currently stands at 7 billion cubic meters per year, is expected to hit 25 billion cubic meters by the end of 2015, comprising 10 billion cubic meters from Turkmenistan, 10 billion cubic meters from Uzbekistan and 5 billion cubic meters from Kazakhstan.

By then, the three lines, built by CNPC and its central Asian partners, would have a combined capacity of 55 billion cubic meters per year.

Line A was launched in December 2009, and Line B in October 2010. The building of Line D of the pipeline is expected to be launched at the end of this year.