Famous 'Ruhr coalfield' is situated in which of the following countries ?

The Ruhr coalfield (Ruhrgebiet) is located in the state of North Rhine-Westphalia in Germany. It is named after the Ruhr River, a tributary of the Rhine. Historically, this region was the industrial heartland of Germany and one of the largest coal-producing areas in the world. The availability of high-quality bituminous coal facilitated the growth of massive iron and steel industries during the 19th and 20th centuries. While coal mining in the region has significantly declined in the 21st century due to environmental policies and economic shifts, the Ruhr remains a major urban and industrial complex. Other countries mentioned have their own distinct coal regions, such as the Kuznetsk Basin in Russia or the Nord-Pas-de-Calais in France, but the Ruhr is synonymous with German industrial history.