China’s ports are experiencing a large backlog which experts say could impact the supply chain for months to come, even though contracts have been extended and some ships haven’t seen land in 18 months. Months at sea without a break has taken its toll on crews, with fatigue and mental illness a threat to safety, reports say.The pandemic has thrown the shipping industry into chaos with covid outbreaks cropping up at ports like the one in the Chinese province of Guangdong, a busy container port. Canceled flights, locked down communities and suspended trade along its coastline has created a large back log. Access to ports is restricted and with planes grounded, it is difficult to move workers to swap crews.