Vehicle taxation should be eco-friendly : Changes to vehicle taxation to focus on reducing pollution were proposed by a research panel to the Japan Environment Agency on Wednesday. The panel, headed by Kyoto University Prof. Takamitsu Sawa, proposed in its report to impose two kinds of vehicle taxation calculated on the basis of weight and exhaust emissions, such as nitrogen oxide and suspended particulate matter. The Transport Ministry Council for Transport Policy in May called for the introduction of vehicle taxation based on fuel efficiency. According to the agency's proposal, eco-friendly vehicles, such as electric and natural-gas vehicles, would have lower tax rates.