The city administration of Bangkok, Thailand revved up its anti-exhaust campaign yesterday by launching 20 motorcycle patrol teams to nab smoke-belching vehicles which may have eluded stationary checkpoints. Each team of one city policeman and one traffic policeman will prowl city streets twice a day. Their initial focus will be Sukhumvit and Rama IV roads covering seven districts. The mobile teams will supplement the 50 stationary checkpoints to test vehicle emission throughout the city. Originally there were 30 checkpoints but since March 1, the city has added another 20 checkpoints.