The Verzasca River is also considered to be the cleanest river in the world. It is located in a valley in Switzerland ' s Italian-speaking region of Ticino. ഈ പർവ്വതം നദി 30 km long and ആദ്യമായി at an altitude of 2864 മീറ്റർ. Verzasca പ്രവാഹം to the south, where it flows into the mountain lake Maggiore.