Bus companies will be required to run cleaner vehicles to reduce air pollution, the environment minister said. Sarah Liao Sau-tung, the secretary for environment, transport and works, said the franchises granted to bus operators would include a requirement that their fleets comprise the most environmentally friendly buses available. 'When they change the bus, we will not simply ask them to use vehicles of Euro IV standard, but the ones with the latest feasible technology,' she said. 'We know that there are already hybrid [petrol-electric] buses available, but we have to wait for a while for [hybrid] double deckers to be developed.' Euro IV is a set of emission standards applying to new vehicles sold in the EU from last year. The condition would be added to the government's franchise agreements with the bus companies when they came up for renewal, Dr Liao said. Official figures show there are more than 5,900 buses on the road, down from 6,359 five years ago. Two-thirds of the fleet's engines meet only Euro II standards for emissions of key pollutants nitrogen oxide and particulate matter, which date from 1996. Speaking on an RTHK radio programme yesterday, the minister said the government would also work hard to reduce the number of buses on the roads and create more pedestrian areas. The Transport Department on Friday announced plans to restructure bus routes with the aim of cutting the number of buses by 100 to ease traffic and reduce air pollution. In the past three years, 204 routes have been restructured, five rerouted and three scrapped. Dr Liao was speaking after government officials disclosed that HK$12.6 million would be spent on 36 highly fuel-inefficient luxury saloons. However, they also said most of the official fleet of 1,071 cars would be replaced with environmentally friendly vehicles by 2014. Edwin Lau Che-fung, of Friends of the Earth, welcomed the government move to press bus companies to switch to buses using cleaner fuel, saying bus emissions accounted for about 10 per cent of respirable pollutants. 'We hope the bus companies will study introducing hybrid double- or single-deckers,' Mr Lau said. The two main bus operators, Citybus and New World First Bus, said as yet no manufacturer was producing hybrid double deckers but they would opt to buy Euro IV buses if feasible. A Kowloon Motor Bus spokesman said market developments and the maturity of the technology would decide whether it used hybrid buses.