NGOs as new Guardians of the Treaties? Analysing the effectiveness of NGOs as decentralised enforcers of EU law

The European Union is increasingly resorting to a decentralised enforcement strategy in which it relies less on the Commission-initiated infringement procedure, and more on domestic litigation by particularly NGOs. In order to better understand whether this is a suitable strategy to tackle the compliance deficit, we need more insight into NGOs as decentralised enforcers of EU law. What do NGOs do to stimulate domestic compliance, and is this a potentially effective alternative to the centralised enforcement strategies? Analysing the actions by the German NGO Deutsche Umwelthilfe in relation to the Ambient Air Quality Directive, reveals high potential for the role to be played by NGOs. This exploratory case illustrates that particularly the strategy of flooding the country with a wave of legal proceedings was effective in increasing the salience of the topic, thereby indirectly releasing those capacities that the authorities had still lacked to comply.