In December 2009 the first line, Line A, of the Trans-Asia pipeline to China opened, creating a second major market for Turkmen natural gas.  By 2015 Turkmenistan was delivering up to 35 billion cubic meters per annum (bcma) to China. China is the largest buyer of gas from Turkmenistan, via three pipelines linking the two countries through Uzbekistan and Kazakhstan.  In 2019, China bought over 30bcm of gas from Turkmenistan, making China Turkmenistan's main external source of revenue.