The article discusses how people's decisions about pollution can be influenced by their sense of morality. When individuals consider the impact of their actions on the environment and others, they may choose to reduce their consumption of harmful goods, even if it costs them personally. This moral behavior can lead to lower pollution levels, especially when people act in a way that they would want everyone else to follow. Interestingly, the optimal environmental tax remains the same whether people act out of self-interest or altruism.