More cities in Jiangsu, including Suzhou and Wuxi, have outlined rapid transit rail routes to link with Shanghai's metro lines.

On Wednesday, residents and company owners said the new extension brought great convenience to their lives.

Wang Jia is an office clerk in Shanghai but lives near Huaqiao, a town located in eastern Kunshan.

"Before the new extension opened, I had to take a bus to Anting, take line 11 and then shift to other lines to travel to my destination," he said. "The extension to Huaqiao will greatly shorten my daily commute."

Lee Han-ling, a manager from Taiwan at Hongta Textile Co in Kunshan, said the line saves both time and money for the thousands of people who need to travel between Shanghai and Kunshan on a daily basis.

"Businessmen in Kunshan make frequent business trips to Shanghai because of the cities' close business connection. Although the high-speed railway is good, it takes a lot of time to check in, wait, and get to your destination," he said.

"Sometimes we chose to drive, only to find that we were caught in a serious traffic jam."

Lee suggested to extend the subway further into downtown Kunshan, as most of the factories, including his textile factory, are clustered downtown rather than in Huaqiao.