非法倾倒垃圾to illegally leave things that you do not want next to a road, in fields, in rivers, etc.
There are significant penalties for those who fly-tip. 针对非法倾倒垃圾的人有高额罚款。
Companies that fly-tip their waste will be prosecuted. 非法倾倒垃圾的公司将被起诉。
See: fly-tipping