This is illegal dumping, the unlawful deposit of waste larger than litter onto land. It includes waste that has been dumped on private land and can be a variety of waste types such as bags of rubbish, whitegoods, or waste from a residential demolition.
Report this to your local council. They manage, and help prevent, illegal dumping. Penalties apply to anyone carrying out illegal dumping.
The council can issue a clean-up notice to the polluter if they can be identified.