Charlie Puth, the pitch-perfect singer who has become a viral star, Tuesday played an intimate set to recognize an entrepreneur who has turned sanitation needs in Kenya into an eco-friendly business.

Puth, who said he had become more accustomed to playing arenas, sang before little more than 100 people at a New York award ceremony of Global Citizen, the anti-poverty activist organization.

The group honored David Auerbach, the founder of Sanergy, a start-up that designs affordable toilets. Sanergy franchises the toilets to low-income residents in Kenya, with the waste picked up daily and converted into fertilizer, energy and other renewable, in-demand products.

A UN report in 2015 said that one in three people in the world lacks basic sanitation, with open defecation carrying grave risks to long-term health.

"In New York, we have toilets, we have sewers and we have treatment plants -- and it's a luxury," Sanj Sanampudi, Sanergy's chief financial officer, told the concert.

"What we're doing at Sanergy is trying to make that accessible to everyone, forever," he said.

Global Citizen presented a grant of $10,000, which Sanampudi said would bring another 2,000 people onto the network of Sanergy. The firm says its toilets are used more than 53,000 times daily and directly or indirectly have created more than 900 jobs.

Hugh Evans, the chief executive officer of Global Citizen, said that such entrepreneurship lay at the heart of the UN-backed goal of ending extreme poverty by 2030.

The concert with Puth -- who ended his set with "See You Again," his falsetto-driven ballad with Wiz Khalifa whose video is the second most-watched of all time on YouTube -- is one of a series of events by Global Citizen leading up to its annual concert on September 23 in Central Park.

The concert aims to put pressure on governments to maintain foreign aid -- a timely goal with President Donald Trump vowing to slash US assistance -- to preserve progress on global development.

Stevie Wonder, Green Day, The Killers, Pharrell Williams and The Chainsmokers will play the concert -- whose tickets are free to fans who pledge to take actions such as petitioning their governments on aid.

Source: AFP