Optimal Environmental Tax-Subsidy Regime in the Presence of Increasing Returns

This paper develops a set of three models to study the optimal tax-subsidy regime in an economy characterised by two deviations from the perfect competition model – negative externality from pollution by the "dirty" industry, and increasing returns in the "clean" industry. Its main conclusions are: (1) the optimal single pollution tax is higher than the Pigouvian level; (2) a combination of pollution tax and quantity subsidy increases consumer welfare at a lower level of pollution tax; (3) the optimal pollution tax can be further lowered and consumer welfare further increased if the quantity subsidy is supplemented by a lump-sum subsidy.