Ensuring access to water, sanitation, and hygiene (WASH) for all requires a thorough understanding of the many contextual complexities that influence access to these services. Complexities spanning environmental, economic, political, and social dimensions, amongst others, can intersect and compound to hinder sustainable access to WASH for certain demographics or entire communities. This is of particular importance for challenging contexts where conventional WASH approaches are ineffective. Targeted approaches are required for these contexts to ensure that communities are not left behind in pursuit of the Sustainable Development Goals. Review of WASH literature identified seven broad types of challenging contexts: challenging environments, transient or environmentally-dependant communities, climate vulnerable communities, remote communities, poor urban communities, refugee camps, and emergency contexts. This review explores the intersecting complexities affecting access to WASH in these challenging contexts and how failure to understand the interconnectedness of these complexities has resulted in WASH solutions that are unaffordable, not inclusive, or unsustainable. To our knowledge, this review is the first of its kind. We emphasise the need to unpack intersecting complexities affecting WASH in challenging contexts, and we believe that incorporating such an approach early in WASH programs can ensure that intersecting complexities are accounted for in the design of WASH solutions. Ultimately, this novel lens may provide critical guidance for WASH programs in challenging contexts, ensuring that WASH solutions are contextually appropriate.

确保所有人都能获得水、环境卫生和个人卫生 (WASH)，需要彻底了解影响获得这些服务的许多背景复杂性。环境、经济、政治和社会等方面的复杂性可能会交叉和复合，从而阻碍某些人群或整个社区可持续地获得 WASH。这对于传统 WASH 方法无效的挑战性环境尤其重要。需要针对这些情况采取有针对性的方法，以确保社区在追求可持续发展目标的过程中不被抛在后面。对 WASH 文献的回顾确定了七大类具有挑战性的环境：具有挑战性的环境、短暂或依赖环境的社区、气候脆弱社区、偏远社区、贫困城市社区、难民营和紧急情况。本综述探讨了在这些充满挑战的环境中影响 WASH 获取的交叉复杂性，以及未能理解这些复杂性之间的相互关联性如何导致无法负担、不包容或不可持续的 WASH 解决方案。据我们所知，本次审查尚属首次。我们强调需要在充满挑战的环境中解开影响 WASH 的交叉复杂性，并且我们相信，在 WASH 计划中尽早采用这种方法可以确保在设计 WASH 解决方案时考虑到交叉复杂性。最终，这种新颖的视角可以为具有挑战性的环境中的 WASH 计划提供关键指导，确保 WASH 解决方案适合具体情况。