Harsh lockdowns are a fact of life in “zero-covid” China. One in September in Chengdu, a south-western city of 20m, stopped locals from visiting tea houses, a favourite pastime. In Sanya, an island-resort town, tens of thousands of tourists were kept off the white-sand beaches in August. In Guiyang, another large south-western provincial capital, it was the boozing that suffered. Apart from forcibly confining almost 6m residents to their…