【正确答案】
Too many cars have created a number of serious problems in our society. Besides congestion, accidents and huge fuel consumption, cars are also responsible for a good part of air pollution in big cities. All the time, they are pumping large amounts of waste gases into the air, which are harmful, causing diseases or even death.
It is no easy task to solve this problem, but some measures may be very helpful. First comes the design and development of clean cars and clean fuels. In Shanghai, some of the public buses have already started to run on natural gas, which does not give off as much carbon dioxide as petrol. Another is to develop modern public transportation systems and restrict the use of private cars. If the public vehicles are efficient and convenient enough, most people will not buy private cars, and the total number of cars in big cities will reduce greatly. Last but not least, people's environmental awareness should be raised, which is the key to this problem.
In a word, the elimination of air pollution needs the collective efforts from the government and the public.