https://www.bmu.de/FA1398-1
FAQ

What are the benefits of an EU environmental policy?

It is easier for the EU to achieve ambitious environmental and climate goals than it would be for Germany alone. Only the EU can adopt effective and binding provisions that are applicable throughout Europe and address the many transboundary environmental problems in an efficient way. The EU guarantees high environmental standards in all member states, which contributes to the well-being of the public and ensures a functioning internal market. EU legislation is the basis of around 80 percent of environmental law in Germany. The EU also helps enforce environmental standards. The European Commission monitors compliance with EU law and can initiate legal proceedings to enforce implementation. If all else fails, the European Court of Justice may impose financial sanctions.