 Whereas in many regional capitals, such as Mendoza, Córdoba, Tucumán, Neuquén, Jujuy, Salta and San Juan, most of the wastewater was treated, in the two largest urban areas of the country, Buenos Aires and Rosario, there was practically no treatment at all, resulting in serious environmental problems.However, in 2008 a bidding process was launched to build a wastewater treatment plant in Buenos Aires.From 1880 until 1980, the national utility "Obras Sanitarias de la Nación" (OSN) was in charge of providing water and sewer services in the main cities, while in smaller cities it was the responsibility of provincial governments, municipalities and cooperatives.