The VET project office conducts road side testing of excessive smoky vehicles islandwide to identify the vehicles that running on the road without proper maintenance. In order to accrue benefits of reduction in unnecessary fuel consumption and preserving of air quality, proper periodic maintenance of vehicle in between emission tests by the user is very much essential. However, according to our roadside inspections, even vehicles especially buses and long vehicles which have passed emission test are found running smoky on roads because of lack of subsequent due maintenance by users.