Scaling up Off-Grid Sanitation To protect human health and the environment, sanitation systems must separate people from their excreta and treat it. This does not just involve technologies but other aspects like finance, government policies and human behaviours must be considered.   Sewers and wastewater treatment plants can assist in providing safe sanitation, but they are expensive and challenging to build, particularly in dense urban areas or where people do not own the land that they live on. In fact, only 45% of the world's urban population have safely managed sanitation; that is where human waste is treated before disposal. Many of these people are instead using off-grid options for sanitation, such as pit latrines and septic tanks. These are physically difficult to empty, especially in areas of high population density, on steep slopes or with a high water table, and pose significant health hazards. The collected waste is often dumped illegally, frequently into water sources. Off grid solutions can only manage waste safely if the waste collection, treatment and disposal is properly considered.   This research will focus on an emerging off-grid sanitation option in the form of container-based sanitation (CBS) across four city contexts where the provision and regulation of CBS is done by different organisations.   In Cap Haitien (Haiti), CBS is provided by an NGO, in Lima (Peru) it is provided by a private company, in Cape Town (South Africa) it is provided by the municipality and in Kakuma Refugee camp (Kenya) it is provided by a private company working with an NGO.    A refugee camp is included as in the future, refugees driven by climate and other factors will make up a significant proportion of the world's urban population.  Interviews will be conducted with the staff working for the CBS provider as well as other organisations that they work closely with, e.g., local government, water utilities and regulators.   To capture the feelings and opinions of the people using the CBS toilets, as well as people using other off-grid sanitation options like pit latrines, a novel smartphone data collection will be used. Participants will complete a short survey several times a week to capture aspects of their mental well-being.  In addition, the data collected will reveal whether current regulations and policies support CBS and whether CBS increases disparities or decreases them.   For example, does CBS without a permanent infrastructure make users feel more vulnerable to eviction, and is the collection of the containers a burden?   Or does it give access to people who would not otherwise be able to use a toilet?  The project will also look at the links with other sectors, specifically waste, energy, transport and solid waste, as if CBS coverage is increased these services will be impacted.   For example CBS relies on road transport and cause additional traffic.   But the use of CBS stops the disposal of waste into rivers so water supplies are cleaner.  Lessons from the project will be shared with other cities who are thinking about implementing CBS, and with other sectors who are working out how they might deliver their services "off-grid". Co-I's have been identified that have expertise beyond sanitation in urban services, and results will be linked and presented at the GCRF Urban Risk Resilience Hub to look more broadly at lessons for off-grid cities. 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.