Best Available Techniques (BAT)
“The most effective and advanced stage in the development of activities and their methods of operation which indicate the practical suitability of particular techniques for providing in principle the basis for emission limit values designed to prevent and, where that is not practicable, generally to reduce emissions and impact on the environment as a whole.”
Definition of BAT by the European Union in Directive 96/61/EC of24 September 1996 concerning integrated pollution prevention and control.