China and Russia are considering expanding a natural gas pipeline that's now under construction. The pipeline is expected to be completed by the end of next year - transporting natural gas from Russia to meet the rising demand for cleaner fuel in China. CGTN's Xu Xinchen visited the construction site and filed this report.

Once the torch is lit, the welding process cannot be interrupted for the next 10 hours.

LI QIANG WELDER "We are using the thickest pipeline ever used in China. The welding process takes five times longer and uses much more bonding wire."

The over 1 kilometer long underwater crossing of the China-Russia gas pipeline is the most crucial and difficult part of the East Route Natural Gas Pipeline. Due to limited space, welders like Li Qiang have to stay alert for the entire welding process. Beyond this kilometer, things are easier - an automated welding machine is saving workers lots of time. The original plan for the pipeline is to transport 38 billion cubic meters of natural gas per year from Russia, and the two sides are contemplating increasing that amount.

WU XUN, DEPUTY PROJECT MANAGER CHINA-RUSSIA EAST ROUTE NATURAL GAS PIPELINE "There are talks to transport an additional 25 billion cubic meters of natural gas from Russia into China, with 10 billion cubic meters of that going through the East Route Natural Gas Pipeline. That could bring up our capacity to 48 billion."

XU XINCHEN HEIHE, HEILONGJIANG PROVINCE "Upon completion, the pipeline will be able to transport more than enough natural gas - a cleaner fuel - from Russia to meet the demand from China's northeast, near the Russian border. The pipeline also extends to more southerly cities, ending in Shanghai. To make sure that happens, experts say trust between China and Russia is crucial."

PROFESSOR BAO WEN HARBIN INSTITUTE OF TECHNOLOGY "It is more important for China and Russia to have mutual trust."

Professor Bao Wen from the Harbin Institute of Technology has over three decades of experience in energy related fields. He says that the pipeline can accelerate the development of China's northeast region, and this in turn could help with the development of its neighbor — Russia's Far East.

PROFESSOR BAO WEN HARBIN INSTITUTE OF TECHNOLOGY "Russian President Putin has been promoting the rise of Russia's Far East. By exporting natural gas into China, Russia can increase the Far East region's GDP and also boost the region's contribution to the entire Russian economy."

The China-Russia East Route Natural Gas Pipeline is expected to start operations by the end of 2019. For welder Li Qiang, the project means more than good pay but also spells out the possibility of better air in China as the country replaces winter coal-heating with natural gas. Xu Xinchen, CGTN, Heihe, Heilongjiang Province.