4 people cleaning up leaves on football field with machines

One of the things I admire about Switzerland is that streets, cities, forests, lakes, mountains - well basically anywhere people go - are so clean here. For example, I noticed the other day - I think it was one of the first days of the United Nations Climate Change Conference in Copenhagen - 4 men using blowing machines to collect leaves that had fallen down from the trees at a football field in Zürich. The field is now completely green again. It looks like it has been vacuumed. By the way, the red building in the back on the first photo below is a school building.

What are your thoughts?