was walking down the stairs at 188 today and saw that someone had made a stupid scribble on the clean green wall. It made me think of an old saying I

1) What does  this mean?

i think it means that what you are doing is wrong

2) Where have you seen this happening?

I've seen this happening all around the world mostly on walls or on the sidewalk

3) Why is it important to fight against this?

so you wont ruin the environment