More than 80 per cent of car owners may unknowingly be driving vehicles that break emission control limits, a test has found. The discovery has sparked calls for smoky vehicle examinations to be extended to all vehicles and more efforts to be made to help raise pollution awareness. The test, which was held a day before World Environment Day on June 5, examined emission levels of 81 diesel and 33 petrol vehicles. Forty-six of the diesel vehicles, mostly taxis and vans, were found to be above both the Transport Department and police emission control limits. Only six petrol vehicles were within the limit. 'Many car owners were left in total disbelief when we informed them that their vehicles had failed the test,' Ringo Lee Yiu-pui, chairman of the Hong Kong Vehicle Repair Merchants' Association, said yesterday. 'Up to now, the Government's efforts have focused on curbing emission pollution generated by diesel vehicles, while those vehicles using petrol or LPG have been overlooked.' The association said the problem could be quickly redressed if owners took more care in maintaining vehicles. The association and the New Century Society, which helped conduct the tests, want the smoky vehicle examinations, applicable to diesel vehicles only, to cover vehicles using other fuels. Mr Lee said: 'The Government should pressure car manufacturers into making maintenance manuals of all their car models available to garages so that mechanics will not have to rely on basic techniques to fix problems.'