The first paragraph of Article 174 of the Treaty on the Functioning of the European Union (TFEU) provides that the Union is to develop and pursue its actions leading to the strengthening of its economic, social and territorial cohesion. The Cohesion Fund which is established by this Regulation should, therefore, provide a financial contribution to projects in the fields of environment and trans-European networks in the area of transport infrastructure.

Specific provisions concerning the type of activities which can be supported by the Cohesion Fund, in order to contribute to the investment priorities within the thematic objectives set out in Regulation (EU) No 1303/2013, should be laid down.

The Union should be able to contribute, through the Cohesion Fund, to actions in pursuit of its environmental objectives, in accordance with Articles 11 and 191 TFEU, namely energy efficiency and renewable energy and, in the transport sector outside the trans-European networks, rail, river and sea transport, intermodal transport systems and their interoperability, management of road, sea and air traffic, clean urban transport and public transport.

It should be recalled that where measures based on Article 192(1) TFEU involve costs deemed disproportionate for the public authorities of a Member State and financial support from the Cohesion Fund is provided in accordance with Article 192(5) TFEU, the polluter pays principle is nevertheless to apply.

It is not possible for investment in housing, other than that related to the promotion of energy efficiency or renewable energy use, to be eligible for support from the Cohesion Fund as it falls outside the scope of support from the Cohesion Fund as defined in the TFEU.

It is important to ensure that, in promoting risk management investment, specific risks at regional, cross-border and transnational level are taken into account.

Complementarity and synergies between interventions supported by the Cohesion Fund, the ERDF, the European territorial cooperation goal and the Connecting Europe Facility should be ensured, in order to avoid duplication of efforts and to guarantee the optimal linkage of different types of infrastructure at local, regional and national level, and throughout the Union.

In order to address the specific needs of the Cohesion Fund, and in line with the Union strategy for smart, sustainable and inclusive growth, it is necessary to set out within each thematic objective laid down in Regulation (EU) No 1303/2013, the Cohesion Fund-specific actions as 'investment priorities'. Those investment priorities should set out detailed objectives, which are not mutually exclusive, to which the Cohesion Fund is to contribute. Such investment priorities should form the basis for the definition of specific objectives within operational programmes that take into account the needs and characteristics of the programme area. In order to increase flexibility and reduce the administrative burden through joint implementation, the ERDF and the Cohesion Fund investment priorities under the corresponding thematic objectives should be aligned.

A common set of output indicators to assess the aggregated progress at Union level of the implementation of operational programmes should be set out in an Annex to this Regulation. Those indicators should correspond to the investment priority and type of action supported in accordance with this Regulation and the relevant provisions of Regulation (EU) No 1303/2013. The common output indicators should be complemented by programme-specific result indicators and, where relevant, by programme-specific output indicators.

In order to amend this Regulation with regard to certain non-essential elements, the power to adopt acts in accordance with Article 290 TFEU should be delegated to the Commission in respect of the amendment of the list of common output indicators set out in Annex I to this Regulation. It is of particular importance that the Commission carry out appropriate consultations during its preparatory work, including at expert level. The Commission, when preparing and drawing up delegated acts, should ensure a simultaneous, timely and appropriate transmission of relevant documents to the European Parliament and the Council.

Since the objective of this Regulation, namely to strengthen the economic, social and territorial cohesion of the Union in the interests of promoting sustainable development, cannot be sufficiently achieved by the Member States but can rather, by reason of the extent of the disparities between the levels of development of the various regions and the backwardness of the least favoured regions and the limit on the financial resources of the Member States and regions, be better achieved at Union level, the Union may adopt measures, in accordance with the principle of subsidiarity as set out in Article 5 of the Treaty on European Union. In accordance with the principle of proportionality, as set out in that Article, this Regulation does not go beyond what is necessary in order to achieve that objective.

In order to allow for the prompt application of the measures provided for in this Regulation, this Regulation should enter into force on the day following that of its publication in the Official Journal of the European Union,