The soot included in the exhaust gas from a diesel-engine vehicle (Nissan LD20, 2 liters) has been eliminated completely (100 %) independent of the load and cruising speed by a noveltechnique using a combination of discharge plasma and oil dynamics. As far as we know, this is the first success in suppressing the black exhaust gas. The NOx (NO2 + NO) and SOx components have also been reduced about 70 % at a lotation number of 1200 rpm and a load of 7kg-m (the maximum torque at 1200 rpm is about 11.4 kg m), corresponding to 60 % of full load. This simultaneous treatment has become possible by using oil. The SOx elimination is the first report in our investigation. Thus, the worst three air pollutants, soot, SOx and NOx, are removed simultaneously.