This document discusses the concepts of adequacy and sustainability of pension systems from the perspective of the International Labour Organization (ILO). It addresses how societies define adequate pensions, balancing adequacy with sustainability lessons from reforms in Europe, and how to close global coverage gaps. Key points include: adequacy is defined nationally based on social contracts; European reforms have focused on sustainability but reduced future benefit levels; non-contributory pensions are important to protect those with broken careers and lower incomes from poverty; and expanding non-contributory pensions is critical to closing global coverage gaps and providing basic income security to the growing elderly population in developing regions.