In Kiambu county on the outskirts of Nairobi, diesel fumes hang over traffic like a second weather system.
Frederick Njoroge Kariuki, 17, has spent many afternoons peering into the tailpipes of matatus. These ubiquitous minibuses power Kenya’s public transport system, and Kariuki wondered if pollution had to be accepted as the price of movement.
This is personal for him. He remembers being 12 and struggling with allergic bronchitis, a chronic lung condition that can be brought on by air pollution.
Over 300 km away to the west, Miron Onsarigo, 17, grew up in Kisumu, close to the Ugandan border, but breathing the same exhaust smoke that chokes road travel across East Africa.
The two met in 2023 after being admitted to the same cohort at M-Pesa Foundation Academy in Thika, central Kenya. They ended up in the same physics class and by 2024, their conversations had narrowed to two main issues: climate change and air quality.
At the academy’s science and engineering club, they began with a question. Why were pollution control technologies priced beyond the reach of the people most exposed to vehicle emissions? “What if we built this from materials that have no scrap value?” Kariuki recalled asking.
Their answer was HewaSafi, Swahili for “clean air”: a five-stage filtration device to fit into vehicle exhaust systems. The first version, built in 2024, took about three weeks to develop. The school provided access to a fully equipped laboratory, while their patron and project adviser, Peter Kiiru Muthondeki, helped guide them.
But the key was their use of locally available waste materials as ordinary as coconut shells, discarded batteries and spirulina algae. “We have tested the prototype on matatus using school-provided sensors and emerged with emissions reductions of roughly 93%,” Kariuki says, before adding that the pilot system is not yet commercially deployable.
When it does reach that stage, the young founders say, the edge in the market may well be lower costs: KSH 15,000 (USD 115) versus KSH 50,000 (USD 390) for imported systems.
HewaSafi’s potential to make a difference on the continent is part of a pattern across the five African teams recognised for this year’s Earth Prize, which spotlights teenage environmental innovators. They were among 35 young scholars selected by the adjudicating panel from around the world.
The seven regional winners, announced on 12 May, each received USD 12,500 to help accelerate their innovations. HewaSafi emerged as the top team from Africa. A global winner is expected to be announced on 29 May. Since 2021, the organisers say, the prize has reached 21,000 students in 169 countries and territories and awarded more than USD 500,000 “to turn ideas into impact”.
In Africa, from polluted air and degraded soil, to wasted textbooks and menstrual inequity, students are responding to environmental challenges they have experienced firsthand. What connects their projects is a belief that solutions should be practical, affordable and rooted in local realities.
As Kariuku told Dialogue Earth: “Africa has its own playbook.”
From biomimicry to waste redistribution
Thousands of kilometres away, in Egypt’s Nile delta, students Ziad Kotb (17), Kareem Ahmad Abd Elkareem (17), Mostafa Mohammed (16) and Nader Syed (16) looked at the rising soil salinity degrading farmland around them. They turned, improbably, to a well-known local fish.
Their project, Terraskipper, draws inspiration from an amphibious fish adapted to muddy terrain – the mudskipper. They have imagined a soft robot that crawls through degraded farmland, monitors salinity and acidity, and potentially plants seeds without disturbing fragile soils.
It is an example of biomimicry – solving human challenges by emulating designs found in nature. Mostafa described the project as trying to fill a gap in monitoring damaged soil, “without damaging the soil or plants further.”
Two Terraskipper designs are being tested and research has been published in student journals. But the ambition is not only technical. Kareem, for instance, frames it as a challenge to assumptions about who gets to produce global environmental solutions. “Young people have agency,” he said, “because we are not stuck in old ways of thinking.”
One of the two Nigerian teams that made the Earth Prize shortlist is confronting a pervasive challenge in schools across Africa. At their college in Enugu, Ossai Gift Chimdiuto and Ekwueme Chiziterem Noalene noticed that rural students often lack books while other students often discard textbooks after they graduate. From this was born BookBank Africa: used textbooks are collected at schools, sorted and redistributed, supported by a digital tracking platform.
Unlike one-off donation drives, the students envision a repeating system tied to graduation cycles. With the support of their school, they say they have already collected thousands of books and packaged the first tranche for redistribution. The logic is fairly simple: extending the life of books already in use in schools reduces waste, lowers demand for new paper production, and cuts the environmental costs tied to printing and distribution.
As Ekwueme puts it: “It is not just access but the lack of proper use of what we already have.”
Not just a product, a movement
Like many girls her age in Niger State, Nigeria, 15-year-old Raheema Auwal-Panti grew up seeing first hand the challenges many women face in accessing safe, affordable and sustainable menstrual products. A Unesco report on “Puberty Education & Menstrual Hygiene Management” suggests some girls in Africa may miss up to four days of school per month during menstruation. Stigma, poor sanitation and lack of pads can undermine attendance and confidence.
What unsettled Raheema was not only that many women and girls could not afford period products, but that even those widely treated as safe came with a problem. “Conventional sanitary pads,” she said, “are 90% plastic and take 500 to 800 years to biodegrade.”
Raheema’s proposed alternative, PantiPads, is rooted in materials most people would overlook. She is developing the biodegradable pads from agricultural products and by-products: garri (flour made from cassava root), dried banana, plantain leaves, corn husks. She believes these ingredients can be transformed into affordable sanitary products.
Her production plan begins with cleaning and drying the materials, then softening and processing them into absorbent natural fibre layers. Those layers will then be shaped and assembled into practical pads. “The goal is to make something that is safe for girls and safer for the environment,” she says.
For Raheema, the invention is not really about the pad alone. “It’s not a product, it’s a movement,” she says.
PantiPads is a campaign built around menstrual dignity, environmental sustainability and access for girls who cannot afford conventional products.
“The goal is not only to create biodegradable pads,” she says, “but to reduce period poverty, challenge stigma around menstruation, and encourage young people to think differently about waste and innovation.”
To move a step beyond experimentation, she says PantiPads would need research support, funding, manufacturing partnerships, product testing and certification, alongside the less technical but equally difficult task of building awareness in schools and communities.
Some of that groundwork has already begun. Raheema has been speaking on youth platforms about menstrual health, sustainability and access to sanitary products. She uses advocacy and storytelling to open conversations often constrained by silence and shame.
“I want girls to see that solutions can come from what we already have around us,” she says.
These young minds may not have all the answers to Africa’s environmental challenges, but they offer a reminder that impactful solutions often start small and, with the right support, can go on to change many lives.
