After the communists came to power in 1949, there was a large influx of refugees from mainland China to Hong Kong, which was still a British colony at the time. In the 1950s and 1960s, this led to a housing crisis, which resulted in the formation of so-called rooftop slums. Rooftop slums are illegally built flats on the flat roofs of Hong Kong's high-rise buildings. Their construction followed the enormous price pressure on the housing market, forcing people with low to middle incomes to find unconventional forms of housing. Fuelled by the immigration of cheap labour, capital and know-how, the rise of the Special Economic Zone began in the 1970s and 1980s. At the same time, Hong Kong developed into a financial metropolis, so that property speculation continued to lead to rising prices, which were further driven up by the island location with limited land area. The government responded only moderately by building social housing. At the same time, all existing social housing was associated with very long waiting times.
Only way to create housing regardless of the real estate market and the lack of government efforts to address the housing shortage and reduce property prices
The 1971 census reported 27,000 people living in the slums. In 1956, the number was an estimated 450,000. Today, Hong Kong is one of the most densely populated places in the world. Prices in the housing market doubled between 2009 and 2014.