The disappearance of pollution havens under unified environmental regulation: evidence from China’s pig industry

Since 2014, China has implemented a unified environmental regulation policy for the livestock industry. With unified environmental regulations across provinces, does the phenomenon of 'pollution havens' still exist? To address this question, this paper examines spatial variations among provinces and their spillover effects on the pig industry using data on environmental regulations and pig production panels. The results indicate that: (1) Environmental regulation policies are gradually converging across regions. (2) Under unified environmental regulation, the existence of 'pollution havens' in the pig industry is no longer evident. As national regulations become stronger, increasing local regulatory intensity will not affect the number of pig farms in neighboring areas nor lead to significant emigration of such farms. (3) In cases where there are inter-regional variations in environmental regulations, large-scale farmers may relocate to neighboring areas with less stringent regulations; however, under unified environmental regulation, neither small nor large-scale farmers will migrate.