The situation changed in the late 1940s when the Kuomintang retreated to Taiwan with up to 2 million people. After that, because many colleges and universities were located in Taipei City and its suburbs, people from central or southern Taiwan came to Taipei to study or work. This led to a sharp increase in population, causing overpopulation in the Western District. Furthermore, the Danshui River hindered the expansion of Taipei City in a westerly direction. These factors resulted in the development of the Eastern District.