Shenzhen is a major city in Guangdong Province, China, which forms part of the Pearl River Delta megalopolis north of Hong Kong. It holds sub-provincial administrative status, with powers slightly less than a province. Shenzhen was once a market town of 30,000[better source needed] on the Kowloon–Canton Railway. In 1979, Shenzhen was promoted to city-status and in 1980 designated China’s first Special Economic Zone. Shenzhen’s population in 2017 is estimated to be at 12,905,000. Shenzhen was one of the fastest-growing cities in the world in the 1990s and the 2000s.