Uzbekistan has some 3,656 km (2,272 mi) of railroad track in common carrier service (not including industrial lines); separate lines serve eastern and western regions. In 2002, there were also 81,600 km (50,706 mi) of highways, of which 71,237 km (44,227 mi) are hard-surfaced. As a doubly landlocked nation, there is no direct connection to the open sea; the closest route to the sea is to the south through Termiz on the Afghanistan border. Conflict in Afghanistan blocks this route. The Zeravshan River is the largest inland waterway. Uzbekistan had 267 airports in 2001, 10 with paved runways. In 2001, a total of 2,256,400 passengers were carried on scheduled domestic and international airline flights.