Toomanycarshavecreatedalotofseriousproblemsinourworld.Besidescongestion,accidentsandfastfuelconsumption,carsareresponsibleforagoodpartofairpollutioninbigcities.Allthetime,theyarepumpinghugeamountsofwastegasesintotheatmosphere.Thesegasesareveryharmful,causingdiseaseandevendeath.
Onepossiblesolutionistodesignanddevelopcleancarsandcleanfuels.InShanghai,someofthepublicbusesbegintorunonnaturalgas,whichdoesnotgiveoffasmuchcarbondioxideasthepetrol.Butitmaytakedecadesforthenewmodelsofcleancarscompletelyreplacethetraditionalones.
Anothersolutionistodevelopmodernpublictransportationsystemsandrestricttheuseofprivatecars.Ifthepriceofpetrolrisesconstantlyandthepublicvehiclesareefficientandconvenientenough,mostpeoplewillnotbuyprivatecars.Andthetotalnumberofcarsinbigcitieswillreducegreatly.
Onthewhole,theeliminationofairpollutionneedsthecollectiveeffortsfromthegovernment,thepublicandtheenvironmentalists.