Indian vehicle makers are joining the global race to make less-polluting greener vehicles, teaming up with international firms and pouring money into research that could result in commercially viable technologies quickly...[F]irms from top vehicle maker Tata Motors Ltd. to tiny electric car maker Reva are testing options from biodiesel to hybrids, encouraged by growing demand...[also refers to Mahindra & Mahindra, Indian Oil, Reliance Industries, Shell]