Rapid industrialisation and urbanisation have led to extremely high demand for petroleum fuels like petrol, diesel. This has resulted in high uncontrolled emissions leading to extensive damage to the environment. The need to investigate alternative fuels which are less polluting is profound today. While more expensive alternative technologies like battery driven technologies, solar cars are not yet feasible for mass production, efforts to improve existing feasible technologies is necessary. The need of the hour is further optimisation of available parameters like biodiesel blends, injection pressures and other nozzle parameters. Biodiesels are methyl or ethyl ester of fatty acids produced from animal fat and vegetable oils. It can be used in completely pure form or blended with diesel before use. Due to its properties being similar to diesel, little or no engine modification is used. It also provides for easy storage and use. The benefits are many fold with significant reduction in emissions of unburnt hydrocarbons, Particulate matter and Carbon monoxide. Improving emission characteristics of exiting diesel engines can also be done by optimising injection pressures. Fuel injection pressure plays a huge role in combustion characteristics directly influencing emission and performance. The review paper focusses on the use of biodiesel blends and variation of injection pressures in diesel engines and their impact on the performance characteristics and emissions of the engine. © Renewable Energy Research, 2017.