Due to the obvious increase in the environmental and human health concerns produced by diesel engines, there has been a lot of interest in ecologically friendly diesel fuels. Current research and development efforts are focused on water-in-diesel emulsion (WiDE) fuels, which have the potential to reduce nitrogen oxide (NOx) and particulate matter (PM) emissions while enhancing performance and allowing for more efficient energy development in a cleaner environment using existing diesel engines. The current topic is concerned with the WiDE fuel principle, emulsification stability, physio-chemical attributes, latest trends in emulsion fuel, the impact of WiDE fuel on engine attributes and the barriers to commercialization of emulsified fuel. Furthermore, the importance of nanoparticle additives in WiDE, nano-fuel formulation, and their impact on engine attributes are explored. © 2023 The Authors