A woman ducks a gate at People's Square Station Wednesday. Photo: Cai Xianmin/GT

The Shanghai metro plans to start cracking down on fare dodging next week, the city's subway operator announced Wednesday.

Although the details of how the crackdown will work remain under discussion, the announcement highlights an ongoing problem for the metro - passengers who refuse to pay.

The practice of fare dodging got a lot of public attention recently after a video surfaced online showing 21 people bypass the fare gates in 90 seconds at Longyang Station on metro Line 2. Most of the fare dodgers were wearing work suits and hard hats.

The video had been viewed more than 200,000 times by 6 pm Wednesday.

Fare dodging is most prevalent at junction stations, including those near the city's railway stations, such as Longyang Road, People's Square and Shanghai Railway Station, said Lan Tian, a press officer for Shanghai Shentong Metro Group.

"Generally, most fare dodgers are workers who are returning to their hometowns for the Spring Festival," Lan told the Global Times. "They are also sometimes commuters, such as office workers and students, as well as some senior citizens under 70 years old."

Fare dodgers account for about 0.16 percent of all subway passengers, though the figure can be as high as 2 percent or 3 percent in busier subway stations, according to a report in the Shanghai Evening Post. Based on those figures, the practice costs the metro operator about 11,000 yuan ($1,769) a day in lost revenue.

About 6 million people ride Shanghai's subway system every day.

Subway passengers can be fined as much as 50 yuan for not paying their fare.