The neem tree, Azadirachta indica, also known as the Indian Lilac, is well known for its oil extracted from its seed and fruit. It has been used in traditional medicine but has also been investigated for the pest control potential of natural products. Work published in the International Journal of Renewable Energy Technology reports on the production, characterisation and use of neem biodiesel as a green fuel for vehicle engines.
source https://techxplore.com/news/2020-12-sustainable-biodiesel-neem-tree-trans-esterification.html