OVERDUE - Tackling the sanitation taboo across urban Africa OVERDUE interrogates infrastructural trajectories and possible pathways to tackle the sanitation taboo across African cities, a task at the core of the Open Defecation Free campaign and the 2030 SDGs, especially SDGs 6 and 11. Sanitation is critical for urban life,yet it continues to be invisibilised, avoided, systematically un-tackled or at best reduced to a 'cultural, technical or financial problem'. Disposing safely of human waste has long been recognised as a human right, yet we witness a persistent, exculpated and prevailing everyday right violation endured by the vast majority of the urban poor in Africa and worldwide.  With the grid narratives aspirating to reproduce the 19th Century sanitary revolution of the urban global North and the incremental coping mechanisms of the urban poor, most African cities just get by, skirting around the sanitation taboo. OVERDUE aims to provide fresh insights into the 'urban sanitation crisis' by decolonising the way it is framed and tackled. This involves a critical interrogation of urban sanitation trajectories and the links emerging across the sanitation continuum between large-scale infrastructural investments in grid systems vis a vis collective and individual incremental investments by the urban poor in off-grid coping mechanisms.   A sanitary revolution across urban Africa requires a new perspective on the gaps and synergies between grid and off-grid efforts and the spectrum of practices and interventions in between, which reads the sanitary metabolism of a city as a highly complex system- of pipes, energy, matter and social relations - which can produce illness or health, poverty or prosperity, suffering or well-being, stigma or respect for the different women, men, girls and boys engaged  in the management of sanitation. Focusing on three fast growing cities - Freetown (Sierra Leone), Mwanza (Tanzania) and Beira (Mozambique) - OVERDUE examines the sanitation taboo across contrasting colonial legacies, with links to the experiences of Francophone urban Africa.   Our aim is to produce fresh outlooks and robust evidence for effective pathways to equitable sanitation across urban Africa's diversity,  through three work packages (WPs). The first two WPs offer a reframed diagnosis of sanitation trajectories in Mwanza, Beira and Freetown, unveiling their spatial and social configurations and the historical and contemporary taboos that undermine  equitable pathways. WP1 tracks down past, ongoing and projected infrastructural investments in the cities, scrutinising their political economy and approach to  'sanitation deficits'  often through the expansion of sewer systems without secondary treatment. WP2 traces existing off-grid sanitation practices and investment flows by informal dwellers, assessing their outcomes and implications. WP3 expands our critical and propositive enquiry to a wider context to document, debate and evaluate emerging sanitation arrangements that could bridge grid and off-grid arrangements at scale across Francophone, Lusophone and Anglophone urban Africa. The ultimate aim is to contribute to visions for "bridging" policy measures (how do we do it) and practical solutions (what is working best), for whom and why.   We argue that sanitation 'deficits' and 'solutions' need to be de-colonised for the right to sanitation to be realised across African cities. Adopting a post-colonial perspective, we aim to provide fresh insights into how contrasting colonial legacies are imbricated in contemporary urban systems to produce different sanitation trajectories. We draw on intersectionality scholarship to shed light into how people's experiences and opportunities differ depending on gender and other social identities and their diverse, multi-layered and intersecting relations. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.