China’s tight zero Covid policy has been taking a heavy toll on its citizens. Now, it is even forcing workers at its largest iPhone factory to resort to desperate measures to escape the strictest curbs in the world.In videos going viral on Twitter, droves of migrant workers at a Foxconn-owned plant in Zhengzhou can be seen jumping the fence to escape hastily enacted Covid measures that left many of the 200,000 staff grappling with inadequate living conditions.