Oil is a very important item in our lives and also is a major life line in a Nation's development. It is such an essential item that without oil the entire world will come to a grinding halt. The availability of oil becoming scarce has let us to explore for new renewable sources of oil, that shall reduce the dependence on conventional petroleum sources, at the same time build and protect a harmonious relationship between nature and human lives. The environment is to be safe and clean with less toxic gas emissions. Several alternative fuels are considered for use in diesel engines. The potential alternative fuels are liquid fuels, like vegetable oil and vegetable oil methyl ester (biodiesel). In the present work, the emission characteristics were experimentally investigated using pongamia methyl ester (PME) blends with diesel (B20) alongwith 10% diethyl ester (DEE) additive. From this analysis, it was found that the maximum reduction in exhaust smoke level was22% and the carbon monoxide level decreased by 16.6% with the 20% pongamiamethyl ester as compared to that of the diesel at full load. The effect of di-ethyl esteras fuel additive with 20% pongamia methyl ester blends were also investigated. It was observed that the diethyl ester with 20% pongamia methyl ester showed an improvement in the emission levels with 6.6% reduction in exhaust smoke level and 50% and 17% reduction in the carbon monoxide (CO) and hydrocarbon (HC) emissions respectively as compared to that of diesel. The oxides of nitrogen emissionswere found reduced to 17.47% for 10% diethyl ester with B20 blend compared to that diesel fuel. © 2020 Elsevier B.V., All rights reserved.