The Fourth Aliyah
The Fourth Aliyah was a direct result of the economic crisis and anti-Jewish policies in Poland, along with the introduction of stiff immigration quotas by the United States. Most of the immigrants belonged to the middle class and brought modest sums of capital with which they established small businesses and workshops. Tel Aviv grew. Notwithstanding the yishuv's economic woes, with an economic crisis in 1926-1928, the Fourth Aliyah did much to strengthen the towns, further industrial development and reinstate Jewish labor in the villages.
In all, the Fourth Aliyah brought 82,000 Jews to Palestine, of whom 23,000 left.