0 . 3   km ▁of ▁vi ad uct s ▁( 9 0 . 6 % ▁of ▁route ▁length ), ▁ 2 5 . 8 7   km ▁of ▁t unn els ▁( 5 . 1 % ), ▁ 1 2 . 9   km ▁of ▁cut ▁and ▁fill ▁( 2 . 5 %) ▁and ▁ 9 . 2 2   km ▁of ▁brid ges ▁( 1 . 8 %). ▁A ▁ 2 1   km ▁tunnel ▁connect s ▁Th ane ▁and ▁Vir ar , ▁of ▁which ▁ 7   km ▁will ▁be ▁under se a . ▁The ▁under se a ▁tunnel ▁was ▁chosen ▁to ▁avoid ▁dam aging ▁the ▁thick ▁veget ation ▁present ▁in ▁the ▁area . ▁The ▁cor rid or ▁will ▁begin ▁at ▁the ▁under ground ▁station ▁in ▁the ▁Band ra - K ur la ▁Complex ▁in ▁M umb ai , ▁and ▁then ▁traverse ▁ 2 1   km ▁under ground ▁before ▁emer ging ▁above ▁ground ▁at ▁Th ane . ▁ ▁The ▁N H SC RL ▁divided ▁the ▁total ▁construction ▁work ▁for ▁the ▁project ▁into ▁ 2 7 ▁packages ▁for ▁which ▁it ▁will ▁award ▁contract s ▁separately . ▁The ▁N H SC RL ▁flo ated ▁tend ers ▁for ▁the ▁construction ▁of ▁the ▁under se a ▁tunnel ▁on ▁ 2 3 ▁April ▁ 2 0 1 9 . ▁A ▁tender ▁for ▁works ▁between ▁V ad od ara ▁and ▁Ah med abad ▁was ▁flo ated ▁in ▁August ▁ 2 0 1 9 . ▁ ▁Const ruction ▁is ▁expected ▁to ▁begin ▁by ▁April ▁ 2