Based on selected four world’s best-selling carmakers Volkswagen, Toyota, Hyundai-Kia and Honda, compared their CO2 emission performance from passenger cars in China, USA and the EU, the report has analyzed the causes and impacts. Besides, the report also reviewed the progress on governmental CO2 regulations for passenger vehicles among China, the EU and USA and explored the implications of those regulations on automakers’ CO2 performance.#气候与能源