the pipeline runs from siberia's urengoy gas field through compressor plant in pomar, mari el to uzhhorod in western ukraine. from there, the natural gas is transported to central and western european countries. together with soyuz and progres pipelines it forms the western transit corridor in ukraine. it crosses the russian–ukrainian border north of sumy. in ukraine, it takes gas to the uzhhorod pumping station on the ukrainian border with slovakia and to smaller pumping stations on the hungarian and romanian borders. the pipeline crossed the ural carpathian mountains and more than 600 rivers including ob, volga, don and dnepr rivers.