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toomanycarshavecreatedalotofseriousproblemsinourworld.besidescongestion,aidentsandfastfuelconsumption,carsareresponsibleforagoodpartofairpollutioninbigcities.
allthetime,theyarepumpinghugeamountsofwastegasesintotheatmosphere.thesegasesareveryharmful,causingdiseaseandevendeath.onepossiblesolutionistodesignanddevelopcleancarsandcleanfuels.inshanghai,someofthepublicbusesbegintorunonnaturalgas,whichdoesnotgiveoffasmuchcarbondioxideasthepetrol.
butitmaytakedecadesforthenewmodelsofcleancarspletelyreplacethetraditionalones.anothersolutionistodevelopmodernpublictransportationsystemsandrestricttheuseofprivatecars.ifthepriceofpetrolrisesconstantlyandthepublicvehiclesareefficientandconvenientenough,mostpeoplewillnotbuyprivatecars.
andthetotalnumberofcarsinbigcitieswillreducegreatly.onthewhole,theeliminationofairpollutionneedsthecollectiveeffortsfromthegovernment,thepublicandtheenvironmentalists.