The elephants in the city

A man is driving on a city bus with a newspaper on his knee. From time to time, he rips a piece off, ripping that piece into smaller ones and throwing them out the window. A passenger standing near him asks:
-Excuse me, why are you throwing pieces of paper out the window?
-I’m chasing away the elephants
-Chasing elephants? There aren’t elephants in the city.
-Well that means it's working!