Manufacturing supply chains in southern China have improved significantly since March when the country was still grappling with the coronavirus crisis, but companies are still reporting disruptions in terms of transport and logistics, a survey on Tuesday showed.More than 78 per cent of the 172 companies that took part in the American Chamber of Commerce in South China survey said they had no supply chain difficulties, an increase of 46 per cent since March.Of the 22 per cent of respondents that…