With its limited natural resources, Hong Kong depends on imports for virtually all of its requirements, including raw materials, food and other consumer goods, capital goods, and fuel. Under its unique status as an international free port, entrepôt trade, mainly with China, flourished until 1951, when a United Nations embargo on trade with China and North Korea drastically curtailed it. This situation, combined with the need to export and with the availability of cheap labour, led to the establishment of competitive light industries and a transformation of the economy in the early 1960s. The market economy and the laissez-faire policy of the British colonial government provided flexibility for further industrialization and the incentive and freedom, from the late 1960s, to attract foreign investment and financial transactions. In succeeding years, with China adopting a more open foreign policy, entrepôt trade rapidly revived, while Hong Kong–China trade surged. Hong Kong developed not only in manufacturing, trade, and shipping but also as a regional financial centre and as an agent in China’s pursuit of modernization. The tertiary (services) sector of the economy now makes up some four-fifths of the gross domestic product (GDP).