Dark, foul-smelling water in Karo river raises alarm in Barbil. Fresh concerns over pollution in the Karo river surfaced on Friday after residents reported dark and foul-smelling water flowing through the river near Barbil, allegedly due to the discharge of wastewater from an upstream industrial unit. Acting on information from the water supply department, the Water Corporation of Odisha (Watco), which draws water from the Karo river for Barbil town, collected samples for testing and.