▁been ▁found ▁in ▁and ▁near ▁the ▁Y ellow ▁River ▁in ▁L anz hou . ▁ ▁On ▁April ▁ 1 1 , ▁ 2 0 1 4 ▁L anz hou ▁officials ▁ad vised ▁residents ▁not ▁to ▁drink ▁tap ▁water , ▁because ▁ben z ene ▁levels ▁were ▁ 2 0 ▁times ▁the ▁national ▁limit ▁of ▁ 1 0 ▁micro gram s ▁per ▁liter . ▁The ▁city ▁water ▁supply ▁sus pected ▁industrial ▁chemical ▁production ▁to ▁be ▁the ▁cul prit , ▁similar ▁to ▁what ▁happened ▁in ▁the ▁ 2 0 0 5 ▁J il in ▁chemical ▁plant ▁explos ions . ▁ ▁Earth qu akes ▁L anz hou ▁experiences ▁earth qu akes ▁regularly , ▁although ▁usually ▁at ▁low ▁intens ities . ▁ ▁In ▁ 1 9 2 0 ▁a ▁large ▁earth qu ake ▁was ▁experienced ▁killing ▁more ▁than ▁ 1 0 0 , 0 0 0 ▁people ▁in ▁N ing x ia ▁and ▁Eastern ▁G ans u ▁province , ▁although ▁only ▁ 4 2 ▁were ▁killed ▁in ▁L anz hou ▁itself , ▁the ▁low ▁number ▁being ▁attributed ▁to ▁the ▁strong ▁yet ▁flexible ▁nature ▁of ▁the ▁wooden ▁buildings ▁in ▁the ▁city . ▁ ▁Sport ▁The ▁ 1 4 , 0 0 0 - cap acity ▁North west ▁University ▁for ▁National ities ▁Stadium ▁is ▁one ▁of ▁the ▁main ▁sports ▁ven ues ▁in ▁the ▁city . ▁It ▁is ▁mostly ▁used ▁for ▁football ▁games . ▁A ▁new ▁sports ▁center ▁complex , ▁including ▁a ▁stad ium ▁with ▁a ▁capacity ▁of ▁ 6 0 , 0 0 0 ▁spect ators ▁and ▁a ▁sw imming