Question

How will i agree my friend not to throw garbage here and there

Answer 1

first i will tell him not to throw garbage and tell him the harms.if he doesn't listen then i will tell to teacher.then also he doesn't listen i will take strict action against him

Answer 2

I will tell about the cleanliness, and spread awareness among the people who are in his surroundings, as, if they are well-aware, they will teach him, say him, not to through garbage here and there. If he doesn't obeys, I will take this to the class leader, and then to his parents. As, they can easily change his attitude.
Hope this will help you.