Almost a year to the day since the first protest boat to China by Greenpeace was forced out by the military, the campaigners have returned, this time with a car. The 'SmILE' car - small, intelligent, light and efficient - which runs on half the fuel of a conventional car, was unveiled at Auto Shanghai 97 yesterday. Unlike last year's confrontational anti-nuclear campaign by the MV Greenpeace, which was forced out of Chinese waters on June 12, this year's visit is legal. More than 250,000 people are expected to visit China's largest car show, where Greenpeace's aerodynamic car will be displayed alongside 500 leading vehicle makers. The SmILE, based on a Renault Twingo and converted by Swiss engineers for US$1 million (HK$7.74 million), can cover 100 kilometres on less than 3.5 litres of petrol, says Greenpeace. Only two such vehicles exist but Greenpeace is challenging carmakers to adopt their fuel-efficient features. The international executive director of Greenpeace, Thilo Bode, who believes China is the key to the ecological future of mankind, is anxious to interest China in the vehicle before firms from the United States, Europe or Japan get there first. 'If you use European cars for China and every household has a car, we have a real environmental problem - not just in China but on the planet,' he said. Greenpeace claims the SmILE halves fuel consumption and reduces emissions. The engineers designed it to run most efficiently at lower speeds.