Thousands of protesters, many wearing masks, participated in an unauthorised march from Tsim Sha Tsui to Cheung Sha Wan. They were protesting against an emergency law and the mask ban it ushered in, gathering at the Clock Tower in Tsim Sha Tsui on Saturday afternoon. Protesters were also at Sha Tin where hundreds assembled in the New Town Plaza shopping mall.   Hong Kong has been rocked by more than four months of anti-government protests sparked by a now-withdrawn extradition bill. (Photo:…