The diesel engine has a higher enduring and thermal efficiency than the spark ignition (SI) engine. In order to partially replace the diesel, biodiesel incorporated diesel is used in the compression ignition engine to meet the growing demand for the energy. Biodiesel is not the only alternative solution. It is renewable, its use allows reductions in oxides of nitrogen and carbon into the atmosphere. In contrast with diesel, the elevated blend (diesel & biodiesel) kinematic viscosity affects the atomization of fuel in the combustion which reduces the combustion pressure and temperature. Addition of ethanol in the blends of biodiesel-diesel enhances the hot flow, cold flow, thermo-physical properties and oxygen content of the biodiesel incorporated burning fuel. By the experiments, it is concluded that, for all blends nitric oxide emission is less than pure diesel this may be because of the increase in the percentage of oxygen, which is being contributed from both pongamia biodiesel and ethanol which further reduces the nitric oxide emission. In contrast to a biodiesel blend, hydrocarbons (HC) emission of biodiesel blend containing ethanol is slightly more but less than mineral diesel. The carbon monoxide (CO) emissions increased as ethanol concentration increases in the burning fuel. As engine load increases, smoke opacity increases. But for the higher concentration blends, smoke opacity is somewhat superior with respect to diesel fuel for lower loads. In this paper, assessment of ethanol as fuel additive to biodiesel incorporated diesel burning fuel on tail end emission characteristics in compression-ignition (CI) engine is reported.