The indicator measures to which extent the states ensure that the members of the public concerned have access to a court of law or other independent and impartial body to challenge the substantive and procedural legality of any decision, act or omission relating to public participation in decision-making in environmental matters.

This indicator is an arithmetic average of expert answers to questions on a scale from 0 (worst) to 3 (best): (16.1) To what extent does the law entitle members of the public concerned to challenge the substantive legality of any decision, act or omission relating to decision-making in environmental matters which is subject to public participation?; (16.2) To what extent does the law entitle members of the public concerned to challenge the procedural legality of any decision, act or omission relating to decision-making in environmental matters subject to public participation?; (16.3) To what extent does the law require that a court of law or other independent and impartial body hear challenges to substantive and/or procedural legality?; (P16.1) In the last 5 years, have public interest environmental or natural resource cases been filed before a court, tribunal or other body? If court records are not public information, check media reports.