As Chinese Premier Li Keqiang started his seven-day tour of Russia and Europe, the China National Petroleum Corp. announced it has approved the design of the so-called Power of Siberia project to deliver natural gas from eastern Russia to China. Work on the project, which has been 10 years in the making, would begin next year, the CNPC said from Beijing Thursday.

Russian Prime Minister Dmitry Medvedev said Thursday Moscow is prepared to offer “comprehensive assistance” to Russia’s Gazprom and China’s CNPC in designing, building and operating the $400 billion project, Itar Tass news agency reported.  

The deal would supply China with an average of 38 billion cubic meters of gas over three decades, helping the country replace coal with cleaner natural gas to help reduce the country’s alarmingly high urban smog levels. It’s scheduled to begin delivering gas to China’s main energy consumption centers in 2017.

Li will visit Moscow Oct. 12-14 to strengthen Russia-China cooperation. Trade between the two countries hit a record $89 billion last year, according to Bloomberg, citing official Russian data. The premiere landed in Berlin on Friday to meet with German Chancellor Angela Merkel to discuss ways to boost trade and investment ties with Germany, AFP reported.

After visiting Germany and Russia, the Chinese premiere is attending the Oct. 16-17 Asia-Europe Meeting summit in Milan. The meeting comes as China is dealing with pro-democracy protests in Hong Kong and the European Union has stepped up sanctions against Russia. The diplomatic row between Russia and Europe over Russian incursions into Ukraine since December is seen as an opportunity for China to boost business ties with Russia, China’s ambassador in Berlin told Reuters. China-Russia bilateral trade is expected to top $100 billion this year.