After the launch and success of Tata Nano, several auto makers challenged the world's cheapest car by fixing lower prices of their small cars. But now the biggest wonder has appeared in the form of EcoCa Ltd-London based engineering and design firm. The company, EcoCa, has developed the prototype of the cheapest car. The new small car would be a two-seater car with automatic gearbox and convertible roof. It weights only 330 kg very less against Tata Nano's 635 kg. The initial fuel efficiency is around 27-28 kmpl as against 23.6 kmpl of Nano. The prototype has a peak speed of 70 kmph, much lower than Tata Nano's 103 kmph.