From 1950s, large number Mainland Chinese illegally crossed Shenzhen border and migrated to Hong Kong. In order to halt the influx of immigrant, English colonial government setup Frontier Closed Area in 1951, the border zone was extended along side with China’s, nevertheless, it didn’t stop the refugee influx, especially during the great famine (1958-62) and Cultural Revolution (1966-76). In 1974, the Hong Kong government adopted Touch Base Policy, which allows immigrants registering Hong Kong Identity Card as long as they reach urban area (South of Boundary Street in Kowloon). Before the immigrants got the chance to leave New Territories, many of them hid in Wa Shan area in Sheung Shui. They also helped out the other immigrates on the China border, by putting on a white flag as a signal on the peak, once they discovered the way is clear. 30 years later, Hong Kong government loses its legislative and executive power on immigration from Mainland China.