Biofuel development in India centres mainly around the cultivation and processing of Jatropha plant seeds which are very rich in oil (40%).  Jatropha oil has been used in India for several decades as biodiesel for the diesel fuel requirements of remote rural and forest communities; jatropha oil can be used directly after extraction (i.e. without refining) in diesel generators and engines. Once this plant is grown the plant has a useful lifespan of several decades. During its life, Jatropha requires very little water when compared to other cash crops. The Indian Railways has started to use the oil (blended with diesel fuel in various ratios) from the Jatropha plant to power its diesel engines with great success. On 12 September 2008, the Indian Government announced its 'National Biofuel Policy'. It aims to meet 20% of India's diesel demand with fuel derived from plants.