Litter consists of waste products that have been disposed improperly, without consent, at an inappropriate location. Litter can also be used as a verb. To litter means to drop and leave objects, often man-made, such as aluminum cans, cardboard boxes or plastic bottles on the ground and leave them there indefinitely or for others to dispose of as opposed to disposing of them properly.
Large and hazardous items of rubbish such as tires, electrical appliances, electronics, batteries and large industrial containers are sometimes dumped in isolated locations, such as national forests and other public land.
It is a human impact on the environment and remains a serious environmental issue in many countries. Litter can exist in the environment for long periods of time before degrading and be transported large distances into the world's oceans. Litter can affect quality of life.
Cigarette butts are the most littered item in the world, with 4.5 trillion discarded annually. Estimates on the required time for cigarette butts to break down vary. They range from five years to 400 years for complete degradation.
In addition to intentional littering, almost half of litter on U.S. roadways is now accidental or unintentional litter, usually debris that falls off improperly secured trash, recycling collection vehicles and pickup trucks. Population levels, traffic density and proximity to waste disposal sites are factors known to correlate with higher litter rates.
Illegally dumped hazardous waste may be a result of the costs of dropping materials at designated sites: some of these charge a fee for depositing hazardous material. Lack of access to nearby facilities that accept hazardous waste may deter use. Additionally, ignorance of the laws that regulate the proper disposal of hazardous waste may cause improper disposal.
According to a study by the Dutch organization VROM, 80% of people claim that "everybody leaves a piece of paper, tin or something, on the street behind". Young people from 12 to 24 years cause more litter than the average (Dutch or Belgian) person; only 18% of people who regularly cause litter were 50 years of age or older. However, a 2010 survey of littering in Maine, New Hampshire and Vermont in the United States, placed litterers aged 55 and over at less than 5%. The same observational study estimated that 78% of litterers are male. In 1999, research by Keep America Beautiful found that 75% of Americans admitted to littering the last five years, yet 99% of the same individuals admitted that they enjoyed a clean environment.