The guidance clarifies aspects of the Directive such as the descriptions and threshold criteria of regulated activities and the definition of an "installation".
The guidance was recommended by EU regulators in 2004 after a study found wide variation in national interpretations of terms such as "installation", "technically connected" and "directly associated" (ENDS Report 352, p 55 ).
The guidance is based in part on a list of answers to frequently asked questions from member states that were not published by the Commission because of concerns about its legal status. The Commission says the information is unofficial and cannot be used in legal proceedings. Final judgments on the Directive’s interpretation can only be made by the European Court of Justice.