A study panel proposed halving the automobile tax on environmentally friendly vehicles in a report to the Tokyo metropolitan government on Wednesday. The group, chaired by Tokyo University Prof. Naohiko Jinno, has been studying ways to balance automobile taxes in light of environmental problems in the metropolitan area. The group also called for a tax hike for vehicles that are environmentally unfriendly, effectively saying that the tax on an automobile should reflect the amount of damage that the automobile will cause to the environment.