Jatropha is not the only option for producing biodiesel. The Botanical Survey of India has identified over 300 species with non-edible, oil-rich seeds. As India has a chronic shortage of edible oils and imports it, non-edible oils are recommended for using in transport and other sectors.

Species with biodiesel potential include: pongamia, jatropha, neem, mahua, rubber and sal. The Planning Commission evaluated these and identified pongamia (Pongamia pinnata to scientists; karanj in Hindi) and jatropha as the most promising. Finally, jatropha was recommended for large-scale plantation because the biodiesel mission was designed to encourage large numbers of people to grow oil-bearing trees. It was important to recommend a plant that begins to yield quickly. Pongamia can take up to seven years before producing seeds in commercial quantities; jatropha begins doing so in the third year.

While the jatropha-pongamia debate has been more or less snuffed out by governments, some academics and researchers continue to question the wisdom of the choice. As pongamia grows widely all across the country, especially down south, the pongamia camp is stronger in Karnataka (where oil has traditionally been extracted from pongamia), Andhra Pradesh and Tamil Nadu.

In 2003, Samagra Vikas, an NGO in Bangalore, conducted a survey to determine the procurement of pongamia, neem and mahua seeds and the quantity of oil produced in the districts of Tumkur and Kolar in Karnataka and Gudiyattam in Tamil Nadu. The results were impressive (see table: So obvious, so undermined). Udipi Srinivasa of the Indian Institute of Science, Bangalore, estimates pongamia oil trade, controlled by the Mumbai commodities market, is to the tune of one million tonnes, mostly going into soap and lubricants.

The transit passes of the past three years with the Chhattisgarh MFP Federation show about 200 tonnes of jatropha seeds are available each year in the state. Pongamia seeds, on the other hand, sell in local markets for about Rs 6 per kg, and transit passes show 1,000 tonnes of pongamia seed is traded. Pongamia grows by the roadside and many have taken up its plantation, and officials estimate about 3,000-4,000 tonnes of seed are available. This means 0.25-1 million tonnes of oil, from already available seed. The other advantage with pongamia is that it is found in regions that badly need economic development, like Bastar.

Pankaj Oudhia, agriculture scientist who’s done most of his work on herbs, worries that large-scale plantation of jatropha, about which very little is known, could be disastrous. He fears toxicity of the seed and carcinogen in fumes of jatropha oil. Pongamia is as hardy and drought resistant as jatropha, and has a deeper root system that can draw from depths of 10 metres depths without competing with other crops. It needs very little care and studies show good tolerance of waterlogging, slight frost, salinity, and all types of soil