When is an EIA required?
Member States are obliged to adopt all measures necessary to ensure that, before development consent is given, projects likely to have significant effects on the environment by virtue, inter alia, of their nature, size, or location are made subject to a requirement for development consent and an assessment with regard to their effects on the environment. By ‘project’ is understood the execution of construction works or of other installations or schemes as well as other interventions in the natural surroundings and landscape, including those involving the extraction of mineral resources.   The Directive does not apply to projects the details of which are adopted by a specific act of national legislation, since the Directive’s objectives are then seen as being achieved through the legislative process.11 (Arts 1 and 2.)
The determination of whether a particular project is ‘likely to have significant effects on the environment’ is fundamental since it is only those projects that are required to undergo an EIA. This determination, often referred to as ‘screening’, is facilitated by the listing, in Annex I, of projects which are always considered to have significant environmental effects, thereby making an EIA compulsory. Among the project types listed are thermal power stations with a certain output, integrated works for the initial smelting of cast iron and steel, and the construction of motorways. Changes to or extensions of listed projects are also subject to compulsory EIA, provided that they in themselves meet any applicable thresholds set out in the Annex.
With respect to projects listed in Annex II, the situation is more complicated. For these projects the Member States must determine whether they shall be made subject to an EIA either through a case-by-case examination or by setting thresholds or criteria, or a combination of both methods. When making this determination the criteria set out in Annex III must be taken into account. These criteria relate to the characteristics and the location of the project, and to characteristics of the potential impact. It is not permissible to establish criteria and/or thresholds taking account only of the size of projects, without also taking their nature and location into consideration.^
Thresholds or criteria may be used to determine when projects should be made subject to an EIA without undergoing a screening as described in the Directive, as well as to determine when they need not undergo either EIA or a screening procedure. However, both criteria and thresholds are meant to facilitate examination of the actual characteristics of any given project in order to determine whether it is subject to the requirement to carry out an EIA.      The Court of Justice has accordingly made clear that when a competent national authority receives a request for development consent for an Annex II project, it must carry out a specific evaluation as to whether, taking account of the criteria set out in Annex III, an EIA should be carried outd4 It has also stated on numerous occasions that the scope of the Directive is wide and its purpose very broad.15
In ascertaining whether a project is to be made subject to an EIA it is not only the direct effects of the works envisaged that are to be taken into account but also the environmental impact liable to result from the use and exploitation of the end product of those worksd6 It is thus not only the environmental impact of the construction of, for example, a motorway or the extension of an airport that is to be considered, but also the impact of their subsequent use. A project’s potential impact must also be examined jointly with other projects, including other kinds of projects.17 It should thus not be possible to circumvent the Directive’s objective by the splitting of projects, since they must anyway be considered jointly. It is also not acceptable to leave out of consideration any part of a project because it is located in another municipality or even another Member Stated8
The Court of Justice has made clear that if consent has been granted for a project listed in Annex II without it having been examined whether an EIA was required, the competent authorities are obliged to take, within the sphere of their competence, all measures necessary to ensure that the project is examined in order to determine whether it is likely to have significant effects on the environment and, if so, to ensure that it is subject to an EIA. These measures may include the revocation or suspension of a consent already granted. This obligation applies even if it has repercussions for third parties, such as users of the land concerned.w In such a situation the pertinent provisions of the Directive thus have direct effect.
When a Member State decides to require a determination, as described in the Directive, for projects listed in Annex II, the developer shall provide information on the characteristics of the project and its likely significant effects on the environment as specified in Annex IIA. If the competent national authority decides that an EIA is required, the determination must state the main reasons for requiring an EIA with reference to the relevant criteria listed in Annex III. If an EIA is not required it shall state the main reasons therefore with reference to the relevant criteria, and, where proposed by the developer, also state any features of the project and/or measures envisaged to avoid or prevent what might otherwise have been significant adverse effects on the environment. The determination shall be made available to the public. The competent authority shall make its determination as soon as possible and within a period of time not exceeding ninety days from the date on which the developer had submitted all the information required. In exceptional cases, the deadline may be extended. (Art 4.)
In exceptional cases, Member States may exempt a specific project from the provisions of the Directive where the application of those provisions would result in adversely affecting the purpose of the project, provided the objectives of the Directive are anyway met. This is without prejudice to the provisions in Article 7 on projects that are likely to have significant effects on the environment in another Member State. If making use of this right to exempt a project, the Member State concerned must inform the Commission, prior to granting consent, of the reasons justifying the exemption. Similar information must be made available to the public concerned. (Art 2.)
Member States may also decide, on a case-by-case basis, not to apply the Directive to projects, or parts thereof, that have defence or the response to civil emergencies as their sole purpose, if they deem that such application would have an adverse effect on those purposes. (Art 2.)
Importantly, the Directive does not require an EIA to be carried out with respect to projects that are not listed in either Annex I or Annex II, even if such a project is de facto likely to have significant effects on the environment.
-  On the terms ‘project’ and ‘construction’ see Case C-275/09 Brussels Hoofdstedelijk Gewest andOthers ECLI:EU:C:2011:154, paras 20, 24, 27, and 38.
-  However, a legislative act ‘which does no more than simply “ratify” a pre-existing administrativeact’ is not sufficient to exclude a project from the ambit of the EIA Directive. The objectives of theDirective must have been achieved by the legislative process. Joined Cases C-128/09 to C-131/09,C-134/09, and C-135/09, Boxus and others ECLI:EU:C:2011:667, para 48. Whether a legislative actsatisfies these conditions must be amenable to review. Ibid, para 54.
-  Case C-2/07 Abraham and Others ECLI:EU:C:2008:133, para 38.
-  Case C-244/12 Salzburger Flughafen EU:C:2013:203, para 30.
-  Case C-531/13 Marktgemeinde Strafiwalchen and Others ECLI:EU:C:2015:79, para 42.
-  See, inter alia, Case C-72/95 Kraaijeveld and Others ECLI:EU:C:1996:404, para 31; Case C-435/97 WWFand Others ECLI:EU:C:1999:418, para 40.
-  Case C-2/07 Abraham and Others (n 12), para 43.
-  Case C-531/13 Marktgemeinde Strafiwalchen and Others ECLI:EU:C:2015:79, para 45.
-  Ibid, para 46; Case C-205/08 Umweltanwalt von Karnten ECLI:EU:C:2009:767, para 55. 19 Case C-201/02 Wells ECLI:EU:C:2004:12, para 65; and Case C-244/12 Salzburger Flughafen(n 13), paras 46—48.