Shanghai lockdown: How Covid tests China's 'Great Firewall' This video can not be played To play this video you need to enable JavaScript in your browser. Shanghai lockdown: How Covid tests China's 'Great Firewall' Close As millions of people continue to stay at home under strict lockdown in Shanghai, videos appearing to show their desperation and frustration have surfaced and gone viral. Usually such clips would not get past China's censors, known as the 'Great Firewall'. But the sheer volume of the clips has made it difficult for censors to keep up. Many are also being passed around in private...