Vienna is the capital and largest city of Austria. It is the 6th-largest city by population in the European Union and the largest of all cities on Danube river. Vienna is regularly recognized as the most liveable city in the world.

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​In 2014, the City Council adopted the Smart City Wien Framework Strategy 2050. The goal is to reduce carbon dioxide emissions by implementing more renewable energy generation while incentivising building insulation to lower the overall heating demand.