In conclusion, I agree that tax is the most effective way in internalising negative externality because the event of externality, the market will not be able to work more efficiently so the government interference. The problem will be more or less depending on type of impact by the government to collect the tax increase to increase in price. When price increase effect in demand decrease and used in substitute good . The decision level of production and consumption of private often consider the cost and the private benefit, but not considered the damage to another person. Therefore, the government's policy to increased taxes in marginal private cost reduces problems caused by negative externalities and the government used tax revenue to help people who have suffered from negative externalities.