pr ises ▁have ▁moved ▁to ▁an ▁industrial ▁park ▁outside ▁the ▁city ." ▁In ▁ 2 0 1 5 ▁it ▁was ▁awarded ▁China ' s ▁climate ▁progress ▁title . ▁As ▁a ▁city ▁once ▁unable ▁to ▁be ▁sp otted ▁from ▁sat ell ites , ▁L anz hou ▁has ▁taken ▁various ▁measures ▁to ▁combat ▁air ▁poll ution ▁in ▁recent ▁years , ▁having ▁reduced ▁its ▁Air ▁Pol l ution ▁Index ▁at ▁the ▁fast est ▁speed ▁across ▁China . ▁ ▁According ▁to ▁the ▁ 2 0 1 8 ▁W HO ▁database , ▁of ▁ 2 7 0 0 ▁towns ▁listed , ▁L anz hou ▁has ▁the ▁ 1 5 8 th ▁highest ▁level ▁of ▁PM ▁ 2 . 5 ▁poll ution , ▁with ▁an ▁average ▁of ▁ 5 4 ▁micro gram s ▁per ▁cub ic ▁meter ▁( tw ice ▁that ▁of ▁Milan ). ▁ ▁The ▁large ▁particle ▁PM 1 0 ▁remains ▁high , ▁at ▁ 1 3 2 ▁micro gram s ▁per ▁cub ic ▁meter , ▁in ▁part ▁as ▁a ▁result ▁of ▁sand ▁storm s . ▁ ▁The ▁reach ▁of ▁the ▁Y ellow ▁River ▁at ▁L anz hou ▁car ries ▁a ▁high ▁load ▁of ▁s ilt , ▁giving ▁the ▁river ▁its ▁characteristic ▁mud dy ▁appearance ; ▁however ▁water ▁quality ▁in ▁this ▁reach ▁is ▁better ▁than ▁the ▁" f et id ▁out flow ▁that ▁bare ly ▁passes ▁for ▁water ▁two ▁hours ▁down stream " ▁( 2 0 0 8 ). ▁In ▁recent ▁years , ▁several ▁spec im ens ▁of ▁the ▁end anger ed ▁Chinese ▁giant ▁sal am ander ▁have