nonlittering

As a noun terms

is .

As an adjective nonlittering is

not dropping litter.

As a noun litter

is (countable) a platform mounted on two shafts, or a more elaborate construction, designed to be carried by two (or more) people to transport one (in luxury models sometimes more) third person(s) or (occasionally in the elaborate version) a cargo, such as a religious idol.

As a verb litter

is to drop or throw trash without properly disposing of it (as discarding in public areas rather than trash receptacles).

As an adjective nonlittering is

not dropping litter.