The Dutch emissions trading program for NOx was developed as part of national policy to comply with the EU directive on National Emission Ceilings (NEC Directive). According to this directive, the Netherlands are obliged to reduce overall NOx emissions from 490 kilotons in 1995 to 260 kilotons in 2010. Negotiations with the major industry sectors involved resulted in a 2010 target for the industry of 55 kilotons (relative to a 1995 baseline level of 210 kilotons). To limit the costs of this significant reduction a trading system was introduced. Various studies had revealed that the costs of NOx abatement could vary between installations. The total annual abatement costs could be reduced by implementing a system of emissions trading.