the municipal government announced on 15 november a plan to reduce the volume of nox emissions from vehicles to 33,000 tons , approximately 63.5 percent lower than the 1990 level , by the year 2000 ; 6,300 tons of the total reduction is to be accomplished in cooperation with local governments in osaka , kanagawa , and three other areas through the introduction of 310,000 low-pollution vehicles , including 40,000 evs and 35,000 natural gas-fueled vehicles .