Upstream and downstream pollution taxations in vertically related markets with imperfect competition

When two markets are vertically related, the government can control pollution at the upstream as well as the downstream market levels. This paper employs the stylized model of input price discrimination and compares the effectiveness of upstream and downstream pollution taxations. We consider the situation in which downstream firms have heterogeneous abatement technologies and an upstream monopolist performs input price discrimination against them. In order to mitigate pollution, the government imposes input tax on the intermediate inputs and emission tax on the pollutant. We show that the degree of input price discrimination decreases with a rise in the input tax and increases with a rise in the emission tax. We further examine the effect of a green tax reform in which the government changes the source of taxation from input tax to emission tax. We argue that although this green tax reform may reduce the tax revenue of the government, it will certainly increase social welfare.