The first Environmental Impact Assessment (EIA) Directive was adopted in 1985, and amended three times since, in 2003, 2007 and 2009.
During the past five years a process of revision has been carried out on the basis of a Report published in 2009 by the European Commission, outlining both the strengths and areas for improvement. Public consultation was open for five months in 2010, covering a wide variety of issues. The results of this consultation together with the proceedings of the Directive's 25th Anniversary Conference were fed into a revised Directive, approved by the Council on April 14th, 2014.
After one month, on May 14th, the new 2014/52/EU EIA Directive has entered into force. Member States have now until May 16th 2017 to apply the new rules and communicate the national legislation set in place to comply with them.
The new Directive is trying to tackle new challenges emerged since 1985 in areas such as resource efficiency, climate change and disaster prevention and to simplify the rules to assess the possible negative effects of a project on the environment.
The main changes include:

• introduction of specific timeframes to simplify the environmental assessment procedure of each Member State;
• EIA Reports drafting shall be more clear, in order to make them more understandable by the general public;
• should a project causing significant adverse effects on the environment be approved, the developers are obliged to do everything possible in order to avoid or minimize these effects, and the project itself will be subjected to monitoring, using procedures decided by the Member States.

For more information please visit the EIA section in the European Commission official website.
The full text of the new Directive can be found at this link.