As someone who lives in Munich, the logo of "Isarlust EV" immediately jumped out at me. Unfortunately it's linked incorrectly - here's the correct URL: https://www.isarlust.org/ (German only).
Of course, the task is a bit easier for Munich than for other cities, as it doesn't have a lot of possible pollutants upstream of it. The other side of the medal is that the river is hair-raisingly cold, as it comes pretty directly from the mountains...
Of course, the task is a bit easier for Munich than for other cities, as it doesn't have a lot of possible pollutants upstream of it. The other side of the medal is that the river is hair-raisingly cold, as it comes pretty directly from the mountains...