Cib chimneys rau kev tshem tawm cov khoom sib txuas ntawm ntau hom khoom siv cua sov hauv tsev ntiag tug tau nruab ntau zaus. Cov qauv ntawm hom no tuaj yeem ua haujlwm ncaj ncees mus txog 100 xyoo. Tab sis los tsim cov chimneys, ntawm chav kawm, yuav tsum tau ua raws li cov cai