After the outbreak of World War I in 1914, battles between Russian and Prussian troops occurred near Konin. Ultimately, the city came under Prussian control and deteriorated. The economic situation of the town did not improve when, in 1918, Poland regained its independence (see: Second Polish Republic) in the war's aftermath. Living conditions of residents were still miserable, exacerbated by the lack of functioning water distribution and sewer systems. The subsequent inter-war economic crisis was harsh, and conditions did not begin to improve until the "désenclavement" of the town, attributable to the opening of a major railway, between Poznań and Warsaw, and the construction of a canal to Gopło Lake. Jews represented 30% of Konin's population in the 1930s.