Optimal inspection (monitoring) and penalty (fine) for plastic bag ban compliance in Nepal

Several cities in the Global South have implemented a (single-use) plastic bag ban to curb the use of plastic bags. However, these bans are not adequately enforced. Efficient enforcement of the plastic bag ban requires a careful calculation of monitoring and fines for violation of the ban. This paper calculates optimal fines and monitoring for effective enforcement of the plastic bag ban in Nepal. We find at a fine set at NRs 764 per episode of violation, nine out of ten retailers are likely to comply with the ban with the probability of being caught is 82.41%. For consumers, a fine of NRs 222 per episode of violation will ensure eight out of ten comply with the ban with a 74% probability of being caught. Although consumers respond to fines, one in ten still uses single-use plastic bags despite the enforcement measures. More than 90% of retailers comply ban with sufficiently high fines and intense monitoring. Our results highlight municipality can effectively enforce a ban with by a careful combination of fines and monitoring. • Calculates the fine and probability of being caught for plastic bag ban compliance. • Accuracy for consumers' and retailers' compliance are 91.7% and 87.4% respectively. • Fine matters the most for consumers while type of ban matters the most for retailers. • Optimal fine for consumers is NRs 222 with a 74% probability of being caught • Optimal fine for consumers is NRs 764 with a 82% probability of being caught