Research into biodiesel as a greener fuel alternative derived from renewable resources has been increased due to the depletion of fossil-fuel reserves, as well as growing environmental concerns. It is a cleaner alternative fuel that may be utilised in diesel engines without requiring any modifications to the engine. This document provides a synopsis of key research on the engine performance and exhaust emission characteristics of diesel engines that are fuelled with biodiesel blends, as well as the results of those investigations. Based on the engine performance tests, biodiesel blends exhibited greater brake specific fuel consumption and exhaust gas temperature than diesel fuel, but poorer braking power, torque, and thermal efficiency. When comparing engine emissions from biodiesel blends to diesel fuel, it was found that carbon dioxide and nitrogen oxides were greater, but that carbon monoxide was surprisingly lower. The most significant advantage of biodiesel is that it is carbon neutral and does not contribute to the emission of greenhouse gases. It contributes to a reduction in pollution by minimising the release of dangerous and hazardous compounds into the atmosphere, as well as significantly improving the performance of the engine.