Ever wondered what those black spots on city sidewalks are? That's gum. All of it is gum that's been spat out then walked on until it acquires a top embedded coating of city grime.
They are very fixated on clean streets, train etc.
Gum tends to end up everywhere and is super hard to relive once dried.
But there are other high penalities for dirting the streets/parks/houses related offenses.
But then it's a city where you could (theoretically) walk barefoot in the streets without worrying about dirt it similar. Through it's probably not legal either and you do have to worry about burning you feed on the hot asphalt ;=}