Clearing the waterways with litter-picking bots

In 2019 Sidhant Gupta, a student from the University of Hong Kong, was visiting Bali with friends when he noticed people collecting rubbish by hand along the coastline. Speaking to them, he discovered that these were locals who owned shops on the beach; each morning, at high tide, they would paddle out on surfboards or boats and collect the litter with nets, because if the beach was dirty, the surfers would not come. “So, for them,” says Gupta, “it was just for the sake of business.”

Gupta, who was on the brink of completing a project, was seeking a new venture. He had honed his skills in biodesign, mimetics and underwater robotics during his studies and – noting that governments in Asia were also investing more in projects to improve the natural environment – saw a business opportunity in helping to solve the issue of water pollution. He returned to Hong Kong to found Clearbot, a startup that builds autonomous marine craft that can safely and efficiently collect litter from the water. 

Each Clearbot craft resembles a small self-driving boat. The electric-powered bots are emission free and can be charged at solar-powered charging docks. They can also be controlled remotely, using a simple hand-held device, or set to roam autonomously using onboard cameras, sensors and GPS. As the bot navigates a waterway it gathers waste, documenting and photographing each piece it collects in order to provide detailed reports about the quantity and type of litter collected. 

There are other companies that build autonomous craft to perform similar tasks in water, but Clearbot differentiates itself by providing a service. It does not just build the bots, it also runs them for clients, competing for contracts to do clean-up work that would have previously gone to potentially less efficient and more polluting types of boats. As well as litter, Clearbot can deploy to clear organic waste and invasive weeds, such as water hyacinth, and suck up floating oil leaks or break down toxic surface foam in industrial settings. 

“We’re very focused on using automation to cut the operational expense of these things,” says Gupta. “So, we have automated docking, and automated and solar charging, which mean we can deploy anywhere and run remotely, which is quite different from how other people are doing it.”

So far, Clearbot has deployed more than 20 bots across half a dozen regions in Asia for clients ranging from municipal water, drainage and highway departments, to property developers. Accordingly, it has had to boost its engineering expertise with personnel that come with knowledge of how regional governments operate in order to navigate complex regulatory frameworks. “We hired a lot of contractors externally to help us with specific problems in naval architecture and legal innovation,” Gupta explains.

Clearbot received seed funding in 2022, which enabled it to expand rapidly from a three-person team to a company with 18 employees. Last year it expanded from Hong Kong into India, and now has its sights set on Saudi Arabia, Singapore, Dubai and Thailand. Clearbot aims to raise Series A funding this year, allowing it to expand to more far-flung regions without having to compromise on its commitment to further research and development.

Innovating and scaling new products remains crucial to the company’s growth, but it is costly to do so. There are, Gupta admits, products with larger capacity on the market for cargo-carrying and deliveries, but Clearbot currently builds the largest bot that specialises in clean-up. “And we think this is far too small,” he says. The initial Clearbot craft could collect about 80 kilograms per hour before it needed to unload. Now, the company has launched a craft that can collect 200kg/h and carry 1.5 tons before it needs to unload. “We’re trying to move on to the next phase of building a bigger size.”

A lot of the innovation around water clean-up, Gupta reveals, has come from Europe, where the problem, he believes, is not as bad as it is in Asia. “When we compare the volumes, those European startups simply don't work here,” he says. The scale of water pollution in Asia is vast and visible. Litter can be seen clogging up marinas, lakes and rivers in cities, towns and remote rural areas, too. “Governments spend millions trying to clean this up, creating more pollution with diesel-powered boats. We saw an opportunity to do something commercially feasible, scalable and with a massive environmental impact. Being a Gen-Z founder, I felt it ticked all the boxes.”