Hong Kong leader Carrie Lam ruled out a citywide lockdown to fight Covid-19, but a surge of infections meant she could not “preclude” the possibility of postponing next month’s chief executive election. Lam said her government’s response to the outbreak had not been satisfactory, with hospitals and medical staff overwhelmed. Daily infections have surged by about 20 times over the past two weeks. Health authorities reported 1,619 infections on Tuesday, a daily record with around 5,400 preliminary positive cases. Chinese industrial city steps up Covid control A Chinese high-tech industry centre …