News Snapshot: SHANGHAI — The city of Shanghai has discovered a COVID-19 case involving a new subvariant Omicron BA.5.2.1, an official told a briefing on Sunday, signaling the complications China faces to keep up with new mutations as it pursues its "zero-COVID" policy. The case, found in the financial district of Pudong on July 8, was linked with a case from overseas, said Zhao Dandan, vice-director of the city's health commission. Shanghai, in eastern China, emerged from a lockdown lasting around two months at the start of June, but it has continued to impose tough restrictions, locking down buildings and...