The Sava River within the territory of Croatia is much polluted due to the untreated domestic, commercial, public and industrial wastewaters of Zagreb City and the neighboring towns/municipalities. The Government of Croatia undertakes water pollution control of the river by constructing and operating wastewater treatment plants in Zagreb City and these towns/municipalities.

Under these circumstances, CTII had formulated a master plan targeting the year 2015 and the feasibility study focusing on the improvement of the water related environment of Sava River through the JICA Study. Technology transfer to the staff of the Environmental Conservation Division has been conducted under the Study.