In the automotive sector, achieving exhaust emission norms is a big challenge to automotive manufacturers. Automobile exhaust emissions play a significant role in air pollution. The burning of fossil fuels like gasoline and diesel generates harmful emissions like carbon dioxide (CO2), carbon monoxide (CO), Nitrogen oxide (NOx), Hydrocarbons (HC) and particulate matteers (PM). In this study, a review is carried to analyze the emissions of compression injection (CI). Based upon review, the study concludes that the ethanol can be used as the best alternative fuel among all biofuels, because of its compatibility with diesel. Ethanol is fumigated into diesel with minor changes in the engine. Ethanol is fumigated at different percentages to understand its influence on exhaust emissions. In addition to this study discuss the results of exhaust emissions under various operating conditions are discussed and also presented in tabular form. Results show that ethanol. Fumigation with diesel is a good technique to reduce the PM concentration and NOx in the diesel engine exhaust. However, CO & HC emissions are higher in this combination.