China Covid: Rare protest against President Xi before party congress- By Tessa Wong & Stephen McDonell- BBC News, Singapore and BeijingA rare protest attacking President Xi Jinping and China's Covid restrictions has taken place in Beijing, days before a historic Communist Party congress.Video from the scene showed unexplained thick plumes of smoke on the bridge and a man could be heard chanting slogans into a loudhailer.Street-level security has been strengthened with paramilitary police patrolling subway stations and neighbourhoods near the Great Hall of the People where the congress will take place.Authorities are cracking down on the use of virtual private networks circumventing China's firewalls, to restrict access to the internet beyond Communist Party control.Many people who travelled to other cities during a recent National Day holiday found that their online health codes - essential for travel around the country - suddenly indicated they were at risk of Covid infection, preventing them from getting on trains or flights back to Beijing."