A World Toilet Summit has opened in the Indian capital, Delhi, with more than 40 countries taking part.
The four-day meeting will examine solutions and technologies that can be used to provide a basic need for nearly half the worlds population.
According to estimates, 2.6bn people around the world lack access to a hygienic toilet. The United Nations hopes to halve this figure by 2015 as part of its millennium development goals.
In India alone, more than 700 million people have no access to toilets which have proper waste disposal systems.