Sustainable water and sanitation for all: Are we there yet?

The lack of access to water and sanitation services (WSS) of a considerable share of the world population has been challenging the international community for decades. The proposal of the Millennium Development Goals and, later on, the Sustainable Development Goals (SDGs) by the United Nations (UN) intended to act as a blueprint to achieve a more equitable future for all and, in the case of WSS, "Ensure the availability and sustainable management of water and sanitation for all" (SDG 6). However, the current global pandemic further emphasised the importance of WSS, given the increasing asymmetries faced by billions worldwide, and the gaps between high-income and low- and middle-income nations. For this reason, understanding whether low- and middle-income countries have been approximating towards or deviating from the SDG 6 is crucial to derive and communicate key information for the sake of improved public governance and political decision-making. In this paper, we extend a state-of-the-art methodology based on data envelopment analysis for assessing the convergence of the low- and middle-income UN Member States regarding the SDG 6 between 2016 and 2017. We find that, on average, not only did the Member States converge by decreasing the performance spread and the gap between the best and worst practice frontiers, but also the Level of water stress: freshwater withdrawal as a proportion of available freshwater resources was the indicator in which the majority exhibited the worst performances. In the end, we derive possible policy implications, which, as our results show, are aligned with the recent UN reports on the subject.