Internalising the externality is act of making in company’s private benefit or cost and results change in price to reflect full marginal social cost. An externality is defined as a benefit or cost that is imposed on the third parties such as society, other than producer or consumer of goods and services or more simply, an economic side effect. When discussing in negative externalities with used taxes to solve the externality. I agree with use of taxes to make the negative externality Internalising efficiently because of the increased tax on production or consumption will allow the quantity of activity in effective point at socially efficient price and socially efficient quantity. For example, collecting fees from emissions by the government to collect fees emissions of pollutants. In which each industry will pay fee based on the amount of emissions. The government needs to know before the amount of optimum pollution of production of the goods or services that type is how much.