On December 14, 2009, the Central Asia–China gas pipeline was opened, and Turkmenistan began delivering large volumes of natural gas to the China National Petroleum Corporation. Combined design capacity of Lines A, B, and C of this pipeline system is 55 billion cubic meters per annum (bcma), of which Turkmenistan's quota is 35 bcma. By 2015 Turkmenistan was delivering approximately 35 bcma to China, counterbalancing declining exports to Russia, which ended on January 1, 2016. Russia had earlier restricted its imports to about 10 bcma, and then 5 bcma. Russian purchases resumed, albeit in smaller quantities, in 2019.