Shenzhen, a pioneer in China's reform and opening-up, maintained its leading position in the import and export volume among cities in the country between 2012 and 2021, according to the local customs.

Data from the Shenzhen Customs indicated that the city's import and export volume increased from 2.95 trillion yuan ($410 billion) in 2012 to 3.54 trillion yuan in 2021, mainly driven by robust development of private businesses.

Specifically, import and export volume of private businesses, which played an increasing role in boosting Shenzhen's foreign trade, increased from 1.03 trillion yuan in 2012 to 2.16 trillion yuan in 2021, the data showed.

Shenzhen's import of mechanical and electrical products has played a significant role in driving the export of high-tech products, the local customs said.

Inside a production base of TCL China Star Optoelectronics Technology Co Ltd in Shenzhen's Guangming district, 8K ultra-high definition display panels are ready to be shipped overseas, after they are assembled on an automated production line.

The company, focusing on research and development of semiconductor displays, realized 38 billion yuan in import and export volume in 2021, an increase of 10 times over 2012.

The city's export of high-tech products increased from 888.98 billion yuan in 2012 to 996.8 billion yuan in 2021, according to the local customs.