Nord Stream 2 is a 1,234-kilometre-long (767 mi) natural gas pipeline from Russia to Germany running through the Baltic Sea, financed by Gazprom and several European energy companies. Feasibility studies began in 2011 to expand the Nord Stream 1 line and double annual capacity to 110 billion cubic metres, with construction beginning in 2018. It was completed in September 2021, but has not yet entered service. Planning and construction of the pipeline were mired in political controversy over fears that Russia would use it, 1 of 23 pipelines between Europe and Russia, for geopolitical advantage with Europe and Ukraine.

A pipeline is a system of pipes for long-distance transportation of a liquid or gas, typically to a market area for consumption. The latest data from 2014 gives a total of slightly less than 2,175,000 miles (3,500,000 km) of pipeline in 120 countries around the world. The United States had 65%, Russia had 8%, and Canada had 3%, thus 76% of all pipeline were in these three countries. The main attribute to pollution from pipelines is caused by corrosion and leakage