Impact assessment of biofuel from waste neem oil

India is a developing nation with fast growing demand for oil. A major part of the requirement has to be met through imports, as domestic production cannot cater to the current demand. Oil imports put a huge burden on foreign exchange and thus cast negative effects on our economy. So extensive emphasis has been laid on production of biodiesel from sources of non-edible oil, such as Karanja, Pongamia, Jatropha, Mahua, Sal, Neem, etc; as these are abundantly available in India. Neem is an evergreen tree that can handle extremely dry conditions as well as sub humid conditions except freezing, is immune to disease and pest and can grow on poor quality soils including clay, saline and alkaline soils. Its life is over 200 years and its seeds contain 30–40% of oil content. Billions of Neem trees exist all over India and only 25–30% of Neem seeds are collected from them for production of oil, which is estimated to be around 100 thousand tons per annum. This considerable quantity of Neem oil can be produced from the remaining seeds, which shows its vast untapped potential. Neem oil has multiple applications, as after extraction of Azardiratchi, which is used for medicinal purposes, the remaining part of the oil can be used for production of biodiesel. The focus of this elaborate review includes Neem oil as a potential feedstock for biodiesel production, optimization of Neem Biodiesel production and evaluation of engine performance and emission characteristics on Neem biodiesel. © 2021 Taylor & Francis Group, LLC.