The percentage of Poland's Jewish population increased greatly during the Russian Civil War. Following Poland's return to independence, several hundred thousand Jews joined the already numerous Polish Jewish minority living predominantly in the cities. The new arrivals were the least assimilated of all European Jewish communities of that period. Polish Jews formed the second largest minority after Polish Ukrainians, of about 10 percent of the total population of the Polish Second Republic. Jewish representation in the institutions of higher learning began to increase already during World War I. By early 1920s, Jews constituted over one-third of all students attending Polish universities. The difficult situation in the private sector, compounded by the Great Depression, led to a massive enrollment in universities. In 1923 the Jewish students constituted 62.9 percent of all students of stomatology, 34 percent of medical sciences, 29.2 percent of philosophy, 24.9 percent of chemistry and 22.1 percent of law (26 percent by 1929) at all Polish universities. Their number, which remained out of proportion with that of the overwhelmingly gentile population of Poland during the Interbellum, were the probable cause of a backlash.
Proposals to reinstitute the numerus clausus, which would restrict Jewish enrollment to 10 percent of the student body (roughly the percentage of Jews living in Poland) were made as early as 1923. However, as this would have violated the Little Treaty of Versailles, the proposals were rejected. In spite of these earlier objections, Poland later renounced the Treaty in 1934. Polish nationalism and hostility towards minorities, particularly Jews, increased. Discriminatory policies regarding Jews in education in Poland continued the practice of the Russian Empire's numerus clausus policy, implemented by the Empire during Poland's partitions, which restricted, by means of quotas, the participation of Jews in public life. Issues that had earlier been resolved by the Russian Empire were now decided locally, uniting the Poles while dividing the nation as a whole.
Various means of limiting the number of Jewish students were adopted, seeking to reduce the Jewish role in Poland's economic and social life. The situation of Jews improved under Józef Piłsudski, but after his death in 1935 the National Democrats regained much of their power and the status of Jewish students deteriorated. A student "Green Ribbon" League was organized in 1931; its members distributed anti-semitic material and called for the boycott of Jewish businesses and the enforcement of the numerus clausus. In 1934 a group of rabbis petitioned the Archbishop of Warsaw, Aleksander Kakowski, to stop the "youthful outbursts"; Kakowski responded that the incidents were regrettable, but also stated that Jewish newspapers were "infecting public culture with atheism."
Agitation against Jewish students intensified during the economic recession of the 1930s and afterwards, as unemployment began to affect the Polish intellectual strata. There were growing demands to decrease the number of Jews in science and business so that "Christian" Poles could fill their positions. In November 1931, violence accompanied demands to reduce the number of Jewish students at several Polish universities. The universities' autonomous status contributed to this, as university rectors tended not to call in police to protect Jewish students from attacks on the campuses, and no action was taken against students involved in anti-Jewish violence.