Environmental Impact Assessment

The "Environmental Impact Assessment" fact sheet provides information on the environmental assessment of public and private projects that are likely to have significant effects on the environment.

Impact assessment can be defined as the process of identifying the future consequences of an action. The impact represents the difference between what would happen if no action was taken and what would happen if it was.

Based on these definitions and considering their application to the environment, it was possible to create the concept of "Environmental Impact Assessment" (EIA), which is a process of identification, prediction, assessment and mitigation of the relevant impacts (biophysical, social and other) arising from a given development proposal (project).

It is a preventive tool that ensures, through its procedures, the integration of environmental considerations into the decision-making process for a given project. It is a process supported by studies and consultations with public participation and analysis of possible alternatives, whose purpose is to collect information, identify and predict the environmental effects of certain projects. Based on this information, it is possible to identify measures that avoid, minimise or offset these effects, as well as methods for monitoring their progress.

This tool was first established in European law in 1985 through the adoption of the EIA Directive, which underwent several changes over almost four decades of implementation. The most recent amendment was in 2014 with the publication of Directive 2014/52/EU.

The EIA Directive was initially transposed into national law in 1990, and the national legal system, like the European, has been the subject of several revision procedures. The last revision was in 2017 with the publication of the current EIA Decree-Law.

Under this legal system, all projects likely to have significant impacts on the environment must be subject to an environmental assessment prior to their licensing or authorisation. A multidisciplinary procedure is established to conduct the assessment, involving several organisations and stages. This fact sheet is intended to describe it.

Depending on the type of project in question, the relevant EIA authority may be the APA or the CCDR with territorial jurisdictions covered by the data contained in this fact sheet.

This fact sheet concerns mainland Portugal and shall be updated on an annual basis.

Objectives and targets: 
  • Strengthen the integration of environmental considerations into the design, development and implementation of projects and into the decision-making process on them;
  • Assess, in an integrated manner, the significant environmental impacts resulting from the implementation of the projects, in order to support the decision on their environmental feasibility, as well as to analyse a posteriori the effectiveness of the outlined measures;
  • Encourage participatory citizenship, ensuring the possibility of public participation in the decision-making process and promoting dissemination and access to information.
Progress analysis:
Last update: 
Monday, 4 October, 2021