European Union regulations on vehicle emission published as directives have the force of law within EU member states under the provisions of the treaty of Rome. In its early years the European Union of generally adopted regulations which were technically identified with ECE (Economic commission for European) equivalents. This position has changed over the time with the European Union, gradually assuming a major role in formulating automotive emission standards.
Light duty vehicles (Passenger Cars) were the first to be regulated under the ECE Process and their limits have been subsequently amended four times ECE-15, ECE-15/01, ECE 15/02, ECE 15/03, ECE 15/04 from 1970 to 1984. In 1988 ECE adopted Directives ECE 83 (88/76/EEC) which amend Directives 70/220/EEC allows the certification of cars with an engine displacement above 1.4 litres on the basis of US procedure and limits. In practical terms this regulation was not implemented by any European Country in anticipation of adoption by EU of the Consolidate Emission directive or Euro I norms. In 1991 the council of Ministry of European Community adopted the Consolidate Emission Direction 91/441/EEC or Euro I norms. According to the Directive Exhaust emission standard have to be on the basis of new combined ECE - 15 (urban) cycle and EUDC Extra urban test cycle. In contrast to pervious directives a common set of gaseous emission standard will apply to all private passenger cars irrespective of engine capacity. Subsequent in Dec. 93 the Environmental Council agreed more stringent limit for 1996 onwards and these were adopted as Directives 94/12/EC on Euro II norms in March 1994. Compared with Euro I norms separate limits are given for gasoline and diesel fuel vehicles. These represent respective reduction of 30% CO, 55% HC+NOx for gasoline cars and 68% CO, 38% HC+NOx and 55% particulate emission for diesel vehicles. Contrary to the earlier standard, production vehicle must comply with the type approval limits. Based on Auto Oil study Euro III and Euro IV norms has been adopted which will be implemented year 2000 and 2005. The comparative table of EURO I, II, III, IV along with Indian norms is given in table 5, 6, 7, & 8. India introduced emission norms for vehicle for the first time in 1991. Indian norms are behind Euro norms by 8 years although effort is being made to narrow the gap between Euro standard and Indian emission norms.