Littering with ポイ捨て

ポイ捨(す)て is short for ポイと捨(す)てる. It refers to littering small pieces of trash in public places such as streets and parks.

There is a connotation of throwing the trash without thinking about it much, so the term is often used with small pieces of trash, such as drink cans, plastic bottles, candy wrappers, and shopping bags.