Short answers, pulled from the story.
Sanitation refers to public health conditions related to clean drinking water and the treatment and disposal of human excreta and sewage. In its fullest sense it spans excreta management, wastewater management, solid waste management, and drainage of rainwater, though many in the WASH sector narrow it to excreta management alone.
Sanitation systems place barriers between excreta and people to break the fecal-oral route of disease transmission. The F-diagram maps these routes through feces, fingers, flies, fields, fluids and food, and adequate sanitation can reduce diseases such as diarrhea, cholera, hepatitis, polio, ascariasis, schistosomiasis and trachoma.
A 2024 United Nations estimate found that 3.4 billion people lacked safely managed sanitation. A 2017 JMP estimate had put the figure at 4.5 billion without safely managed sanitation, and as of 2015 an estimated 2.4 billion people still lacked improved sanitation facilities.
The United Nations General Assembly recognized the human right to water and sanitation in 2010. The right is derived from the human right to an adequate standard of living and is grounded in human rights treaties, declarations and other standards.
By a rough estimate, for every US$1 spent on sanitation the return to society is US$5.50. A World Bank study found that economic losses to the Indian economy from inadequate sanitation were equivalent to 6.4% of its GDP.
The sanitation ladder, defined by the Joint Monitoring Programme in 2016, is a scale that begins at open defecation and climbs through unimproved, limited and basic, with safely managed at the top. It is used to compare sanitation service levels within and across countries and is particularly applicable to developing countries.
The Indus Valley Civilization shows public water supply and sanitation during the Bronze Age, between 3300 and 1300 BCE. The first sewers of ancient Rome were built between 800 and 735 BCE, including the Cloaca Maxima that emptied into the River Tiber.