On 26 June 2019, the Court of Justice of the European Union (CJEU) issued its preliminary ruling in Case C-723/17 Craeynest. This is the third time in 10 years that the CJEU supports the right to clean air of EU citizens. In two previous cases (C-237/07 Janecek and C-404/13 ClientEarth), the Court held that citizens can challenge the lack of adequate air quality plans. The new ruling broadens the right to clean air, clarifying that it includes the right to challenge how authorities monitor and assess air quality.
More generally, in Craeynest the CJEU took the opportunity to clarify some principles of EU law regarding the intensity of review of scientifically complex assessments. The ruling has, therefore, the potential to strengthen access to justice beyond air quality matters in all environmental case.
Background of the case
The case started in September 2016, when ClientEarth and five other Brussels’ citizens challenged the authorities for their failure to prepare an adequate air quality plan and to measure air pollution where there is the highest public exposure, as the law requires. An independent study by ClientEarth suggested that some of the most polluted areas in Brussels had NO2 concentrations double the highest official records published by authorities. However, Brussels authorities are refusing to measure air quality in the most congested and polluted streets, hiding the real scale of the air pollution problem in the city from the public.
Following a hearing in November 2017, the Court of First Instance of Brussels decided to stay the proceedings and ask two preliminary questions to the CJEU.
The two preliminary questions
The first question addressed the enforcement of the requirements for air quality monitoring set under the Air Quality Directive 2008/50/EC. The Brussels judge asked the Luxembourg court to clarify whether citizens can challenge the authorities’ failure to properly site monitoring stations. This aspect of the case regards, therefore, the right to reliable information about air quality and the ability of citizens to force authorities to install additional stations to collect more accurate data. The key dispute concerned the scope of judicial review and the separation of powers between competent authorities and national courts. The Brussels authorities claimed that courts should not be allowed to interfere with complex technical assessments, such as the choice of the location of monitoring stations.
The second question focused on the issue of how authorities should assess compliance with legal limits for concentration of pollutants in ambient air. In particular, the dispute between the parties was whether compliance should be achieved at each single sampling point within the monitoring network or, on the contrary, based on the average from all monitoring stations within the zone or agglomeration. It is an important question because it is only when limit values are exceeded that the relevant authorities are obliged to adopt an air quality plan that will include adequate measures to tackle air pollution.
The answer of the CJEU
The ruling of the CJEU is a clear step towards ensuring a high level of protection of human health and the environment and wide access to justice in the EU. It clarified that citizens can challenge the adequacy of monitoring networks and that national courts have the power to review and take all adequate measures, such as an order, to make sure that sampling points are properly sited. It also clarified that compliance with air quality limit values must be assessed at each single sampling point and not through an average for the entire zone or agglomeration.
The point of departure of the CJEU’s reasoning is the strong link between the objectives of the Directive 2008/50 on ambient air quality and the EU’s obligations concerning environmental protection and the protection of public health. According to Article 3(3) TEU and Article 191(1) and (2) TFEU, the European Union aims at a high level of protection of the environment and public health, on the basis of the precautionary and preventive principles. The Air Quality Directive puts such objectives in concrete terms. The CJEU sees an important role of citizens and national courts in ensuring the effective implementation of the Directive and securing protection of human health and environment.
The CJEU clarified that the criteria on the design of monitoring networks are central to the structure of the Air Quality Directive. The very purpose of the Directive would be compromised if sampling points were located in such a way that exceedances of air quality limit values may go unnoticed.
The court acknowledged that, in principle, the selection of the sites for monitoring station is reserved to the discretion of competent authorities, on the basis of the evaluation of complex and technical elements. However, such discretion is limited by the objectives of the Directive to protect human health and environment. As a consequence, review by national courts should not be limited to manifest errors, but shall be more intense, even if it regards complex technical assessments.
Crucially, the CJEU held that authorities are required to base their decisions on sound scientific data and to prepare comprehensive documentation that includes evidence supporting the choice of the location of all monitoring sites. That documentation must be updated regularly to ensure that the selection criteria remain valid.
If the citizens have doubts as to the legality and reliability of the monitoring network, they can challenge it before the national courts. Several provisions of the Air Quality Directive set obligations that are sufficiently clear, precise and unconditional. This is the case, in particular, with regard to the obligation to establish sampling points in such a way that they provide information on the pollution of the most polluted locations and the obligation to establish at least the minimum number of sampling points. National courts are, therefore, competent to ensure compliance with this obligation and shall take all necessary measures to ensure that sampling points are sited in accordance with the criteria laid down in the Directive.
As regards the second question, the CJEU stated that, in accordance with the Directive’s purpose to protect human health, it is necessary to assess the actual air pollution levels to which the population is exposed and to ensure that appropriate measures are taken to combat the sources of such pollution. It follows from the general scheme of the Directive that the level of pollution measured at each individual sampling point is relevant, not the average across the entire city. Consequently, the fact that a limit value has been exceeded at a single sampling point is sufficient to trigger the obligation of the competent authority to draw up an adequate air quality plan.
This judgment is another stone in the strong foundation of the right to clean air of EU citizens. While the Janecek and ClientEarth cases had already clarified that citizens can challenge the lack of adequate air quality plans, this was the first test case to reach the CJEU on the enforcement of the provisions on monitoring of air quality. The CJEU broadened the range of legal actions that citizens across the EU can take to enforce the provisions of the Air Quality Directive. This ruling paves the way for new legal actions on air quality issues at a moment when people across Europe are increasingly engaging in citizen science projects to independently assess air quality and questioning official information provided by authorities.
This ruling can strengthen access to justice and accountability of authorities in environmental cases more generally, even beyond air quality matters. Whenever a court case entails the application of fundamental EU principles and objectives, national courts will need to roll up their sleeves and carry out full review of the technical evidence, rather than trusting the assessment carried out by public authorities.