China's Delta outbreak tests limits of zero-tolerance Covid approach

Officials have confirmed that the new outbreak is caused by the Delta strain

The rise of the highly-contagious Delta variant is challenging even the most aggressive Covid-19 containment regimes, an ominous sign as economies look to open up and return to pre-pandemic life.

An outbreak that started at an airport in the eastern Chinese city of Nanjing is testing that country’s zero-tolerance measures, which are some of the most sweeping and comprehensive in the world. New infections are rising by the dozens and seeding subsequent clusters around China despite well-honed systems of mass testing and stringent quarantines. Beijing reported its first locally-transmitted infection in six months Thursday, linked to an outbreak in the southern