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Environmental Impact Assessment

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This is a process for identifying the environmental effects (positive and negative) of proposed developments before planning permission is granted.


Environmental Impact Assessment (EIA) aims to prevent, reduce or offset the significant adverse environmental effects of development proposals, and enhance positive ones. It ensures that planning decisions are made considering the environmental effects and with engagement from statutory bodies, local and national groups and the public.


The legal requirement for EIA comes from Directive 85/337/EEC. This Directive has been amended and is now included in Directive 2011/92/EU of 13 December 2011.  

In Wales, this became law through the Town and Country Planning (Environmental Impact Assessment (Wales) Regulations 2016 [2016 No.58 (W.28)] (external link). You can read guidance on the Regulations in Welsh Office Circular 11/99 Environmental Impact Assessment (EIA).

The Regulations apply to all projects which fall under the town and country planning system. Other Regulations apply to those projects subject to development consent outside this system.

When you need an impact assessment

Applications for planning permission which fall under the regulations must undergo a screening process to see whether they need EIA. The decision on whether EIA is needed is made by us and / or the local planning authority.

If the proposed development is likely to have a significant effect on the environment then it should have EIA. In such cases, the applicant for planning permission must provide the required information so the environmental effects of the development can be assessed. This information, in the form of an Environmental Statement, will then be considered in the determination of the planning application.

The Regulations state that, where an application needs to have EIA, planning permission shall not be granted unless the person determining the application has first considered the environmental information.

Local planning authorities decide in the first instance if EIA is required. This may happen after receipt of a planning application or after a request from a potential applicant, before they submit an application. This is a screening opinion. If the authority decide that EIA is required the applicant can appeal to us for a screening direction.

Call ins

Where we call in an application in or we receive a planning appeal, we will consider whether it needs EIA. We will consider any screening opinion issued by the local planning authority and any advice from our technical advisers.

Environmental statements

If EIA is needed and an Environmental Statement is submitted, then the local planning authority (for applications before them) or us (for called-in applications and appeals) will consider whether the Statement complies with the Regulations. If it doesn’t, more information may be requested to ensure that it does.