Cultures responded to the COVID‐19 pandemic differently. We investigated cultural differences in mental health during the pandemic. We found regional differences in people's reports of anxiety in China over two years from 2020 to 2021 (N = 1186). People in areas with a history of rice farming reported more anxiety than people in wheat‐farming areas. Next, we explored more proximal mechanisms that could help link the distal, historical factor of rice farming to people's modern experience of anxiety. Rice areas scored higher on collectivism and tight social norms than wheat areas, and collectivism, rather than norm tightness, mediated the rice‐anxiety relationship. These findings advance our understanding of the distal sources of cultural differences, the proximal mechanisms, and mental health problems during the pandemics.