Hong Kong has a bustling free market economy highly dependent on international trade. Natural resources are limited, and food and raw materials must be imported. The textile and garment industry is the largest industry. Other industries include plastics manufacturing, electrical and electronic equipment, appliances, metal products, rubber products, chemicals, furniture, jewellery and toys. Shipbuilding, machine tooling and other heavy industries are also important. Hong Kong has become a major market for electronic item. Tourism is a major revenue source. Hong Kong is a major business centre of the world. Located in China, the city is one of the most expensive cities in the world. The mainland China has long been Hong Kong's largest trading partner.