The Polluter Pays Principle (PPP) is a key principle underlying EU Environmental policy. A fitness check on whether the PPP has been effective in the various environmental policies and legal texts at the EU and national level is therefore necessary and substantial regulatory action will be needed to timely address all the identified gaps. The PPP in its implementation should ensure the full internalisation of negative environmental and social externalities. However, it is not fit for purpose in most environmental and climate policies. It is restricted to limited taxation and failing market-based internalisation instruments and does not currently provide any recourse to monitoring, enforcement or compensation for environmental, health and climate damage. The EEB contribution to the PPP fitness check is classified into four categories: environmental effectiveness, economic effectiveness, just transition and justice, compensation and burden of proof.