Environmental economics is asub-field of economics concernedwith environmental issues. It is an areaof economics that studies the impactof environmental policies and devisessolutions to problems resulting fromthem. 'Public economics' is the study ofgovernment policy through the lens ofeconomic efficiency and equity. 'Development economic' is a branchof economics that focusses onimproving fiscal, economic, and socialconditions in developing countries. 'International economics' is the studyof economic interactions betweencountries.