Danny Goodman Tata Motors' Nano, available for commercial delivery from July, has the lowest carbon dioxide (CO2) emission level among small cars. The company says the Nano emits 101 g of CO2 per km, among the lowest in the world for the class. The Nano's gasoline engine technology has been developed by German auto major Bosch. Maruti's A-Star, fitted with the K10 B engine, emits 109 g of CO2, per km, while Hyundai's Kappa engine, present inside the i10, generates 119 g of CO2, per km. The manufacturers have developed these fuel-efficient, low-emission engines primarily for the export market. By 2012, EU emission norms stipulate all cars, plying in Europe to emit less than 120g of CO2 per km. "There is a direct correlation 'between lower CO2 emission higher fuel efficiency," says Anumita Roy Chowdhurv, Associate Director at the Centre for Science and Environment. The Nano, with its lowest CO2 emission, delivers the highest mileage, 23.6 km/litre. While the A-Star travels 19.6 km/litre and Hyundai's i10 gives 18.1 km/litre. In India, automobile emissions are measured by the amount of particulate matter like sulphur dioxide and nitrogen oxide present in tailpipe emissions. Whereas, the amount of CO2, present in vehicular emissions is used as a key indicator of vehicle fitness in Europe. India's Bharat III (Euro III) norms are five years behind those currently enforced in Europe, while Bharat IV (Euro IV) norms, not enforced outside 13 Indian cities, are 10 years behind European benchmarks. Tata Motors says the Nano is BS-III compliant and BS-IV ready.