According to some sources, cigarette butts are the world's biggest litter problem. Cigarette filters are not biodegradable and contain several chemicals harmful to the environment and marine life. If you're a smoker that's on the go, get a portable ashtray. Then you can collect the butts and give them to an organization like this one that recycles them. Cigarette packaging (including the plastic wrap) should also be properly disposed in a garbage bin or brought home with you.