"Globally, India continues to be the country with the highest number of people (597 million people) practising open defecation," says the report --the Progress on Drinking Water and Sanitation-2014 update-- released in Geneva today.
The report jointly prepared by the WHO and the UNICEF says that eighty-two per cent of the one billion people practising open defecation in the world live in just 10 countries.
Despite having some of the highest numbers of open defecators, India does not feature among the countries making great strides in reducing open defecation, says the report.
The UN findings prompted Rural Development Minister Jairam Ramesh to term it as "a huge shame for all of us."
"I have been saying all this for three years now. Sanitation has to become a national obsession. It is a huge shame for all of us," said Ramesh, who took several steps to eradicate the menace of open defecation in the country.
"High GDP growth is all very well but this is most basic fundamental, related to the security and dignity of women. Also we have failed to recognise that poor sanitation is one of the main causes of persistent malnutrition," he told PTI.
The report, however, hails India's immediate neighbour Bangladesh and Vietnam, saying they are among the top 10 countries that have achieved the highest reduction in open defecation since 1990.
Vietnam, Bangladesh and Peru have reduced open defecation prevalence to single digits, it says.
According to the UN, countries where open defecation is most widely practised have the highest number of deaths of children under the age of five, as well as high levels of undernutrition, high levels of poverty and large disparities between the rich and poor.
There are also strong gender impacts: lack of safe, private toilets makes women and girls vulnerable to violence and is an impediment to girls' education, it says.