BlueTEC is a name for engines equipped with advanced NO_x reducing technology for vehicle emissions control in diesel-powered vehicles. In this paper, the working of emission system is discussed. The main aim of the paper is to describe various technologies of Blue-TEC. Different application areas and advantages of Blue-TEC are mentioned significantly. Emissions defeat device allegations is studied. There is a focus on services offered by blue-TEC technologies. Issues in Blue-Tec technology are also taken into account.