Littering is bad because it makes an area look ugly; it is expensive and sometimes difficult to clean; and it is harmful to people, plants and animals. Littering is also bad because it is illegal. People who litter can be fined and charged. read more
Another, more obvious, reason that littering is bad, is that it just looks gross. The trash can contain diseases as well, that can be passed between animas that eat it. If trash is sitting in water, the water becomes contaminated, and when the water evaporates whatever was in the trash in now in the air. read more