The Government should raise taxes on air travel and high-polluting cars in order to help the environment, an important committee of MPs has said. It also said that the 70 mph speed limit on motorways should be reduced or enforced to bring down the amount of carbon dioxide given off by cars The House of Common Environmental Audit committee’s latest report said that transport was the only sector（部门）of the UK where carbon emissions have continued to rise since 1990. It said it was time for the Government to make demand for cheap air impossible by raising air passenger tax. Emissions f