Water is a fundamental human need and key to economic development. Since the beginning of civilization, people have faced problems associated with river and freshwater sharing. To add on to the precarious situation, most of the freshwater rivers are transboundary rivers, i.e. they cross at least one political border, either a border within a nation or an international boundary. Water politics, commonly known as hydropolitics, are politics affected by the availability of water and water resources, which play an important role in transboundary water management. Hydropolitics relate to the ability of geopolitical institutions to manage shared water resources in a politically sustainable manner, i.e. without tensions or conflict between political entities. As the pressures of population and economic growth increase, water resources are under increasing stress. As the stress on water resources increases, the risks associated with the management of transboundary rivers increase exponentially given the hegemonic disparities of the riparians. This gives rise to risks of conflict while generating opportunities of cooperation which can be analysed with the help of risk-opportunity index developed using fuzzy synthetic evaluation technique proposed by Rai et al. (J Hydrol 519:1551-1559, 2014). It has been proposed to formulate a hydropolitical sustainability index (HypSI) keeping in view the circles of blue sustainability (blue indicates water in this chapter) which considers the social desirability, political legitimacy, economical viability, environmental sustainability and technical feasibility aspects of shared water resources. © 2017 Springer Science+Business Media Singapore.