I do not know why the smokers have this bad habit, apparently it is normal for them to finish smoking and throwing their butt on the ground, I think it is a question of education, because as they throw away the butts they also throw any kind of trash or rubbish on the ground , sometimes people are not aware of the year that they cause, especially because those of us who smoke do not have to get hurt because of their vices! Very interesting your subject and it gives a lot to reflect in this sense! Regards!!