A German chemistry professor is starting a 2,700-kilometre swim on Friday down the length of the Danube to highlight the level of pollution in the river. Professor Andreas Fath from Furtwangen University is expected to take three months to swim to the mouth of the Danube in the Black Sea, passing through or along the borders of countries including Austria, Hungary, and Serbia, and ending just kilometres from the Romanian border with Ukraine. The Clean Danube project accompanying Fath says that every day the Danube washes 4 tons of plastics into the sea. “Some Danube countries have neither effe…