Passengers board and depart a train at a metro station in Shanghai. (Photo:Sipa)

A new restriction on the use of loudspeakers in metros will take effect in Shanghai on Dec 1, according to Shanghai Metro on Wednesday.

The move has been supported by many netizens, some of whom have suggested that the rules be rolled out across the country.

Regarding the implementation of the rules, a staff member told local news portal ThePaper that passengers may alert the metro's customer service when they notice any offenses being committed.