Why did Guangzhou expand mainly eastward before the 1980s?

Before the 1980s, Guangzhou’s urban expansion was primarily directed toward the low plains to the east because of significant geographical barriers in other directions.

To the north, the city's growth was restricted by hills, while to the west, the presence of numerous waterways acted as a natural barrier to development. Although the city had previously expanded southward through the construction of new dikes along the Pearl River, the eastern plains offered the most viable land for continued growth during that period. It was only after the 1980s, following an influx of people and rapid economic development, that the city began to expand significantly in all directions, including to the north and south.1