Air pollution caused by heavy traffic is increasing dramatically in bigger cities and the European Union is preparing strict limitations on carbon dioxide (CO2) release on newly produced cars in an attempt to deal with the problem. One helpful solution to the problem could be using cars equipped with engines which run on compressed natural gas (CNG). Cars powered by CNG are more fuel efficient, diffuse fewer toxic gases and are quieter than normal cars. The Czech Republic's Skoda Auto has now presented their new Skoda Octavia prototype powered by CNG. The company is ready to produce greener cars, but is concerned about the lack of gas stations which supply CNG. "Our aim is to produce about one thousand cars with CNG engines during 2008. But there is a question regarding the number of CNG gas stations," Chairman of Skoda Auto, Detlev Wittig said. In the Central Bohemian region of Mladá Boleslav, the Czech deputy prime minister and environment minister, Martin Bursik was able to try filling a car with CNG himself. The new fuel station in Mlada Boeslav was opened by RWE transgas which hopes to open one hundred station by 2020. Bursik drives a car with a bio engine. "The compressed natural gas is one of the most hands on alternative fuels for the future. It is called a bridge leading to the hydrogen based energetic fuels we will use in the future. But before that time comes, we should use this kind of fuel. It is very important that we build up the network of CNG stations and Skoda Auto's prototype car using this kind of fuel," Bursik said. Many conventional cars run by gas or diesel can be converted into CNG cars. Buses can also run on CNG. At the cost of 35,700 euros a CNG bus is more expensive than a less environmentally friendly bus, however after 50,000 kilometres the price difference is expected to even out. There are currently 15 CNG filling stations in the Czech Republic. By the end of this year, there should be around twenty, and there is talk of up to four hundred public CNG filling stations by 2020. The rise in compressed natural gas powered vehicles should be equally dynamic. By 2020, it is estimated there will be 23.5 million such cars in Europe, with an estimated 350 000 - 450 000 in the Czech Republic alone.