Breathable fabric used in field test traps waste and allows only tiny water vapour molecules through Evan Krape, University of Delaware

Families in two Indian cities, Kanpur and Puri, are trying out a new "eco-vapour" toilet system developed by University of Delaware students and researchers.

Sewage from the cities is collected in 55-gallon drums lined with a breathable fabric, allowing water vapour to evaporate.

The fabric is similar to that used in sports jackets and raincoats the fabric allows only tiny water vapour molecules through.

The team is now observing how the fabric performs under varying conditions of heat and humidity, which affect the rate at which water diffuses through the membrane.

These sanitation systems can be used to line pit toilets and other basic sanitary facilities in developing nations.

It helps filter out liquid water from human waste, letting the pure water escape while retaining everything else. Essentially, sewage is placed in a container of this fabric would become dehydrated and therefore less hospitable to bacteria and other disease-causing organisms.

Non-governmental organisation WaterAid India is partnering with the research group.

Sanitation is a major problem in developing nations. In India where millions still defecate in the open, the prime minister has vowed to ensure that every household will have a toilet by 2019.