by Dan Martin SHANGHAI, China (AFP) — Shanghai authorities on Wednesday called for calm as worried citizens swamped online grocery platforms to stock up on food over fears of impending lockdowns in a city struggling to halt a Covid spike. China is experiencing its worst Covid-19 outbreak since the start of the pandemic more than two years ago, with Shanghai posting record-high case counts as the highly transmissible Omicron variant frustrates authorities. China’s biggest city […]