High tax for high polluters : If a vehicle is a heavy polluter, its owner should pay heavier taxes, a task force of Japan's Environment Agency recommends in a report compiled Wednesday. But the report only proposes increasing the burden on old cars and those with diesel engines, and some analysts have expressed disappointment that more vehicles were not targeted. The report proposes tax reductions on low-emission vehicles, which release fewer nitrogen oxides (NOx) and other pollutants, and higher taxes on gasoline-engine vehicles produced before 1978 emission controls were implemented and diesel-engine vehicles produced before 1982 controls.