Why has a Chinese city's lockdown sent aluminium prices to 14-year high?

The COVID-19 lockdown in China's Baise city sent global prices of aluminium to a 14-year high. Baise was locked down on Monday after mass testing identified nearly 100 people with COVID-19. Nicknamed the "aluminium capital of southern China", Baise produces about 2.2 million tonnes of aluminium per year, but the production was impacted due to travel restrictions hindering logistics flows.