Many countries prohibit mask-wearing during demonstrations

Wearing masks at protests is a criminal offence in many parts of the world. France, Germany and many US states prohibit mask-wearing during demonstrations. Canada's law may be the harshest, with penalty of up to 10 years' imprisonment.

In Hong Kong, masked radical protesters have unleashed an unprecedented wave of violence against police officers and innocent people over the past few weeks.

More than 750 suspects have been arrested for committing acts of violence that include arson, assaulting police officers and possession of offensive weapons.

There is a growing voice in the community for Hong Kong to legislate against wearing masks in demonstrations.