The appearance of green fencing across the city of Shanghai has confused and frightened residents living under strict lockdown measures, according to the BBC. The barriers, measuring roughly two meters in height, have been put up with little warning or explanation. They designated “sealed areas,” according to the BBC, marking the apartment blocks they surround as zones where at least one resident has tested positive for COVID-19. Every person living within the fences is required to stay indoors, regardless of their infection status. “No one can get out,” one unnamed man told the BBC, expressing concerns about being able to escape in an emergency. “I feel helpless.” At least one local authority partially explained the barriers as a “hard quarantine” measure, describing it as such—without elaboration—on a notice dated April 23. Shanghai reported a record 39 deaths due to COVID-19 on Sunday, with officials noting that they had registered more than 21,000 new cases of the virus.