What attributes of mandatory waste management policy can enhance the separation intention of residents in China? A behaviour choice experiment

China is facing a severe waste siege. Notwithstanding the several years of mandatory policy implementation, the residents’ waste separation intention remains insignificantly enhanced. Consequently, it is urgent to theoretically answer the question of what type of mandatory policy is most effective. Thus, in the current research, we propose the mandatory policy as a combination of five attributes, that is, economic penalty, social penalty, supervision, charging, and community governance, and conduct a policy choice experiment with 354 participants. The results of the randomized conjoint analysis show that economic penalty, supervision, and community governance are influential determinants of separation intention. The mandatory policy has an interaction effect with auxiliary policies; specifically, community governance and supervision are more effective, while residents are also more willing to pay fines when a points redemption policy or a well-developed infrastructure system is present. The effect of mandatory policy also varies across residents. Females, highly educated, or high-income individuals are relatively more inclined to separate waste, while elders, renters, and residents who have lived in an environment for more than 20 years are less likely to separate. The results of the welfare gain analysis show that strengthening the penalty, supervision, and community governance are also helpful toward improving social welfare. In order for mandatory policies to work better, it is important to continuously improve community governance, raise the cost of violations, vigorously promote waste supervision, perfect the reward mechanism, and improve waste separation infrastructure.