October is the month of strengthening measures against diesel vehicles by nine prefectures.

In order to improve air pollution caused by automobile exhaust gas, nine prefectures (Saitama, Chiba, Tokyo, Kanagawa, Yokohama, Kawasaki, Chiba, Saitama, and Sagamihara) have been banned from the operation of diesel vehicles that do not meet the particulate emission standards since October 2003.
However, some cars running in the nine prefectures and cities still do not meet the emission standards, so it is important to take measures to reduce the number of offending vehicles to zero. Therefore, in the nine prefectures and cities, October is positioned as the strengthening month, vehicle inspections based on the regulations will be conducted, and posters will be posted in service areas and parking areas.