A child puts on a T-shirt in front of a public toilet in a slum area near Pluit reservoir in Jakarta. Reuters

Don’t laugh: Despite its name, the World Toilet Summit has a serious mission. The annual conference, this year held in Surakarta, Indonesia, aims to shed light on the plight of the 2.5 billion people worldwide who lack access to a toilet or sewage system.

Tuesday marked the beginning of the World Toilet Organization's 13th such summit, attended by 400 delegates from 19 WTO-member countries, according to the European Cleaning Journal. Attendees come together to share information and experiences regarding sanitation and toilet problems, as they're critical to every country's public health and economy.

For example, about 1 million children worldwide from diarrhea each year, according to statistics from the United Nations, about the same number as perish from AIDS, measles and malaria combined. In Indonesia, 63 million people have no access to basic sanitation facilities, said Naning Adiwoso, chairwoman of the Indonesian Toilet Association, according to the Bangkok Post.

"For many people in Indonesia, mobile phones are more important than toilets," Adiwoso said. "People defecate in the backyards and think that nature will take its course.... There's a widespread lack of awareness about the importance of sanitation."

At the three-day summit in the central Java city of Solo, speakers from local and international groups discussed how to clean, repair and maintain toilets as well as how to best design public bathrooms. Even in Jakarka, the capital city of Indonesia, some households do not have toilets, and public restrooms are hard to find, Adiwoso said, noting the few that do exist are often in terrible condition, according to the Bangkok Post.

Sanitation has an economic impact as well, reflected by the theme of this year's summit, “Toilets and Tourism.”

“Without good toilets, tourism can’t thrive,” said Jack Sim, a Singaporean citizen who founded the World Toilet Organization in 2001, speaking to the role public toilets play in a city’s potential as a holiday destination. “Toilets are part of the holiday experience.”

On Thursday, the last day of the summit, participants attended the World Toilet Carnival, an event designed to promote sanitation awareness.

“The carnival theme is sanitation and its related technology because we want to educate people on the best practices in sanitation,” said Adiwoso, according to the European Cleaning Journal.