The situation in Changan township had become serious, with young people having left while the aged lived in panic after the farmlands had been abandoned.

"This truly described Changan township before China's reform and opening-up policies were introduced in the late 1970s," said Guo Rongxin, deputy Party chief and head of Changan township in Dongguan, Guangdong province.

"Due to poverty, many young people risked their lives to secretly swim to Hong Kong to pursue their dreams of wealth," he said.

Guo said Hong Kong now has more than 30,000 permanent residents from Changan township, which is situated in the southernmost of Dongguan.

After four decades of development, Changan, formerly an agricultural township, has now become a major production base, Guo said.

"The good investment climate and high government work efficiency are still attracting more and more investors and business representatives from home and abroad to set up their production facilities or start their businesses here," he said.

"Almost all the products sold around the world can be produced in Changan," Guo said with pride.

Dongguan, home to the country's mobile phone giants Huawei, Oppo and Vivo, produced more than 293 million smartphones in the first 10 months, up 6.7 percent this year and accounting for 26.7 percent of the country's total.

Changan's GDP reached more than 55 billion yuan ($8 billion) last year, comparing with only 5.2 million yuan in 1978. Its industrial production hit 194 billion yuan in 2017 compared with about 500,000 yuan in 1978.

"Changan would not have been able to have made such great economic achievements without the 40 years of the country's reform and openingup," said Guo.

When China had just opened its door to the outside world in the early 1980s, many Changan officials found it very difficult to apply for a visa to Hong Kong, so they had to pretend to be sailors to travel there and lobby their fellow townsmen to invest in Changan.

Zhao Xiaoqun, chairwoman of Dongguan Chitwing Technologies, said the Changan township government and related departments have done a lot to serve domestic and foreign investors.

"Electricity supply has not been suspended in recent years, which ensures our production even when the town is experiencing a power shortage," Zhao said.

Zhao's company, a Shenzhen stock exchange listed company, has expanded to between 7,000 and 8,000 workers, up from 1,000 in 2007. The company's annual industrial production has now reached more than 2 billion yuan.

Cai Guodong, Party chief of Changan's Wusha community, said great changes have taken place in his community in the past four decades.

"Now the living standard of most residents in the community can compete with their counterparts from the United States and Europe," he told media.

Most of the residents can now earn more than 100,000 yuan a year and the community pays most of the medical care for them, and the average living space in Wusha community comes to more than 80 square meters, said Cai.