The world needs to build almost 100,000 toilets a day to halve the number of people without basic sanitation by 2015, according to experts at the gathering.
But Jacks Sims, of summit co-organiser the World Toilet Organisation, said at the close of the meeting that it could be done.
"You all think Singapore is so clean," said Sim, juxtaposing a picture of himself defecating in the streets as a child there 40 years ago with a photo this year of a boy in India's tech-hub Bangalore doing the same.
"It was not always like that."
But delegates acknowledged during the conference last week that many countries still have a long way to go.
Some 2.6 billion people -- more than 40 percent of the globe's population -- still do not have access to hygienic toilets that do not pollute water or soil. More than half of them live in India and China.
The United Nations wants to halve that number in the next eight years as part of its Millennium Development Goals.
Delegates pledged in a joint declaration Friday to "facilitate a paradigm shift from disposal-oriented to reuse and recycling sanitation systems."
"It has been noted that there is a need to accelerate the progress on achieving the Millennium Development Goal on sanitation by 2015," the statement said.
Some 400 delegates from more than 40 countries promised to "mobilise governments, UN agencies, financial institutions, corporate bodies, sanitation service providers, local bodies and other stakeholders."
A Swedish delegate said that the cost to achieve the 2015 goal could be achieved for 3.8 billion dollars a year.
"The direct and indirect benefits are tenfold," said Arno Rosemarin, an ecological sanitation researcher from the Stockholm Environment Institute.
Water-borne diseases caused by poor sanitation kill millions worldwide annually, including as many as 1.6 million children from diarrhoea alone.
The four-day summit in New Delhi showcased toilet technologies that could help developing countries -- where most of the loos are needed -- build sanitation systems that do not use water or require expensive infrastructure.
The AfriSan toilet from South Africa is a waterless dry composting toilet that uses solar light and small amounts of peat moss every day to help turn waste into manure.
"To achieve the goals, what is essential is that technology needs to be urgently developed that is suitable and simple of implementation," said Bindeshwar Pathak, founder of the Indian toilet advocacy charity Sulabh (Convenience), the summit host.
"Sewers or septic tanks are not the solutions."
Pathak, inspired by Indian freedom icon Mahatma Gandhi, began to build simple toilets in India in the 1970s and has developed a low-cost system that turns waste into water, fertiliser for crops and biogas to run generators.
The World Toilet Organisation, which was founded in 2001 and aims to make sanitation a key global issue, has 55 member groups from 42 countries.
Pathak and Sim have been widely lauded by organisations such as the United Nations, which has named 2008 as the "UN Year of Sanitation."