Around midnight on a Friday last November, a motorbike pulled up to a nightclub on the darkened outskirts of Dar Es Salaam. The club was hidden behind a nondescript roadside bar near the city's international airport, with plastic chairs and tables and a fridge stocked with bottles of Kilimanjaro beer. The bar's lone customer was watching one of the Die Hard films on TV. Two men got off the motorbike and stepped onto the dusty sidewalk. It was Jay Mitta and Sisso Mohamed, both key names in Dar Es Salaam's singeli scene. A minute later, fellow singeli artists Duke and MCZO, who were scheduled to play at the nightclub that evening, emerged from a taxi.

Just beyond an unassuming door on the side of the club, the party was in full swing. The four artists found a quiet corner and sipped on soft drinks while a DJ played bongo flava, a Swahili take on hip-hop that's dominated the commercial market for years, as well as party-primed dancehall and pop. Duke and MCZO's 1 AM set time came and went. Around 2 AM, the club manager came over and turned on the air-conditioning, shrugging off the delay. By then, Duke was sprawled out asleep on a couch. Sometime after 3 AM, they got the call. MCZO leaned over and woke up Duke with a gentle punch. The pair made their way upstairs to the DJ booth, which was housed in an imposing cage overlooking the dance floor.

Duke, slim and baby-faced, pulled his laptop out of his backpack and perched it in the DJ booth while the sound guy fiddled with MCZO's microphone. The first hit of singeli coursed through the crowd like a shot of adrenalin. Singeli is a bracing listen to the uninitiated—it's fast, anywhere between 180 and 300 BPM, placing it well ahead of drum & bass and even some gabber, with MCs rapping over relentless electronic rhythms. It's rowdy and uniquely Tanzanian, informed by decades of the country's electronic and folk music.

The dance floor went into overdrive. A couple of people sprayed beer on each other. One man triumphantly lifted up a bar stool over his head and ran around. A woman started doing a Chura dance—a kind of Tanzanian twerk. It was a scene of pure joy, a glimpse into the power of a genre born in the neighbourhoods of Dar Es Salaam that has grown to dominate Tanzanian dance floors, airwaves, block parties and festival stages, emerging as the soundtrack to the country's youth.

For many outsiders, Dar Es Salaam is a pitstop on the way to paradise—somewhere to pass en route to the snow-capped peak of Mount Kilimanjaro, the white beaches of Zanzibar or safari hotspots like Ngorongoro and the Serengeti. Its rich musical culture is a confluence of Arab, Indian and African histories and traditions. Ride through the city in a taxi and you're likely to hear taarab (a traditional genre associated with Zanzibar), Swahili jazz or some other form of intoxicating coastal music on the car radio.

Dar Es Salaam is one of the fastest-growing cities in Africa, with a population currently rising by half a million people each year—a rate of growth that has it on track to become the sixth-largest city on the planet by 2100. Like most of its neighbours in East Africa, it's a country of young people, with around 44 percent of the population under the age of 15. High-rise buildings dominate the downtown area near a heavily trafficked port that faces out towards Zanzibar and the Indian Ocean.

Singeli began like most genres do, with artists taking what's come before and twisting it into new shapes using whatever technology they could afford. It borrows heavily from taarab and several other styles that came before it, including mchiriku, which flourished in the late '80s with producers using Casio keyboards reinterpreting taarab and the melodies of the Zaramo tribe. It has ties to sebene, a high-tempo style that can be traced back to the Tandale neighborhood in Dar Es Salaam. It's also influenced by bongo flava, though these days that influence runs both ways, with bongo flava stars like Professor Jay incorporating singeli into their tunes. A new breed of pop-leaning singeli artists has emerged, with the likes of Man Fongo, Msaga Sumu and Sholo Mwamba racking up millions of views on YouTube, while the likes of Duke, MCZO, Sisso and Jay Mitta routinely play stadium gigs to thousands of fans.

Singeli can at times sound bewildering—take the meowing cat noises on Jay Mitta's "Masera," or the eight minutes of air horns and radio samples on Duke's astonishingly quick "Naona Laaah"—but there are no shortage of floor-filling tracks, from Jay Mitta's catchy "Tatizo Pesa" to Bamba Pana's weightless "Lingalinga" to Dogo Suma Lupozi's relatively streamlined "Kazi Ya Mungu Haina Makosa26." When the genre was first brewing a decade or so ago, tracks like these would be played at kigodoro parties. "Kigodoro" means "foam mattress" in Swahili—the parties were named this way because attendees would invariably collapse, exhausted, on any bit of foam they could find after the marathon parties ended.

The kigodoro parties were an incubator for singeli, but the genre's true birthplace is a tiny studio in Dar Es Salaam's Mburahati neighbourhood. Mburahati is a short drive from Morogoro Road, a key artery leading from downtown Dar Es Salaam out of the city, with road signs pointing to Kenya and Zambia. It's typical of the sprawling network of no-frills working-class neighbourhoods in Dar Es Salaam, a city where most people live below the World Bank's poverty line.

Sisso set up his studio in 2013. Before that, he produced music on his laptop in his bedroom, and made money selling DVDs. Sisso's wife and young son live next door to the studio, which functions as a kind of informal gathering spot and community hub. Step inside its steel door and a list of studio rules are written in Swahili on the inner wall: "Don't eat inside," "If someone is recording, don't knock on the door" and, "If you want to record music, you have to pay for it."

I visited Sisso's studio on a muggy afternoon last November. We sat in near-darkness for a couple of minutes, before four neon bulbs switched on above Jay's head. A fan turned, a computer purred to life. Sisso, who had been outside turning on the studio's electricity, walked in wearing tight denim jeans, a Nyege Nyege t-shirt and a yellow SpongeBob SquarePants cap. He sat down on a stool at his computer and started dragging files around. Using Virtual DJ, Sisso took a taarab song and pitched it way up past 180 BPM. He threw in some instrumental loops—first some bass hits, then some snares, and began adding and subtracting elements on the fly. A sound emerged that was unmistakably singeli.

Aside from kigodoro parties, singeli in its early days was heard mostly at weddings. In that respect it's similar to electro acholi, which originated from the Acholi tribal region of northern Uganda with Otim Alpha as its star. And, like electro acholi, singeli artists performing with their laptops presented a cheaper wedding party alternative to traditional music troupes. Sisso told me that taarab musicians didn't take kindly to seeing their music sampled—and their wedding bookings plummet. An informal truce was called and singeli artists started sampling Congolese soukous and Afro House tracks instead, while also making their own foundational rhythms on software like Cubase and FruityLoops.

Jay Mitta outside the Sisso studio in Mburahati

Sisso Records is one of the scene's two main studios. The second is Duke's Pamoja Records, about 1km away. On the way to visit Pamoja from downtown Dar Es Salaam, I passed a busy market on Uhuru Road, with stalls selling clothes, backpacks and suitcases. The street was clogged with dalla dalla minibuses jostling for position. On the roadside a vendor lazily hacked at a stick of sugar cane with a huge knife. Next to him were a dozen or so men who had set up stalls under umbrellas, selling pirated music on USB and CD. This thriving black market has helped fuel the genre's booming popularity, but it means that singeli artists face the same challenge confronting musicians the world over: the need for a steady stream of gigs to generate any kind of income.

Pamoja Records is a small, windowless room fitted with a makeshift recording booth. When I stopped by, a large steel pot of meat stew, prepared by Duke's mother, bubbled quietly by the studio door. Outside, palm trees swayed in the afternoon breeze and a few people spoke softly into their mobile phones. A small child wearing a Tanzanian national team football shirt walked unsteadily into Duke's studio, observed everyone in the room, and started dancing as Duke, wearing a bright blue and red shirt, sat on a disused speaker playing some of his productions, including tracks from his recent album, Uingizaji Hewa.

Duke described his style as "hip-hop singeli," crediting as influences US acts like Busta Rhymes and Eminem plus Tanzanian stars Nikki Mbishi and Professor Jay. He told me that radio stations like EFM, which hosts a weekly three-hour segment devoted to singeli, have been crucial to singeli's rise within Tanzania. These stations, which offer regular competitions to unearth the best up-and-coming DJs and MCs, have seen singeli spread from Dar Es Salaam's working-class neighbourhoods to the cars and homes of the Tanzanian middle class.

The tunes Duke played in the studio were more gnarly and raw than the music I heard in Sisso's studio, falling somewhere between ragga and gabber. "Singeli is different to other music, the samples are changing every second," he said, pulling up his shirt to wipe the sweat off his forehead. "It's fast. The tracks are changing every second. If you've never heard it before, you notice that it changes a lot."

Duke outside his studio

Singeli's journey outside Tanzania can be traced back to a single taxi ride.

Arlen Dilsizian, cofounder of Uganda's Nyege Nyege collective, flew in from Kampala in 2016 on a mission to find Sisso and his network of singeli artists, but he had no connections and no idea where to start. "I had been researching singeli that I'd bought from some mp3 peddlers at Kariakoo, the main market in Dar Es Salaam," he told me. He was particularly drawn to the music of Duke, Dogo Niga and Bamba Pana. "I spent about two days looking for them with no luck, asking various musicians I knew if they knew Sisso. They kept on directing me to the more commercial artists."

Eventually Arlen stepped into a taxi driven by Abbas Jazza, a close friend of Sisso and the entire singeli community who spoke English. They became friends, and Arlen started having Sisso's productions couriered to Kampala. The music on these CDRs was whittled down into Sounds Of Sisso, a 2017 compilation released on cassette through Nyege Nyege Tapes.

The compilation was groundbreaking. The music put singeli on the international map, shining light on MCs Dogo Niga and Makaveli as well as the production talent of Sisso, Bamba Pana and Jay Mitta. Some artists rode this momentum onto global tours, but not all of them were interested in careers in music. Dogo Niga is now a witch doctor living outside Dar Es Salaam, and is mostly inactive as a singeli MC.

These artists make music with little obvious commercial appeal, but they play to increasingly large crowds in Tanzania, living in a parallel world to the pop-leaning singeli stars. The singeli MCs and producers gaining recognition outside Tanzania are not the country's chart-topping stars, but the genre's originators: Sisso, Jay Mitta, MCZO, Duke, Makaveli and Bamba Pana. Their music has been embraced in European experimental circles, with Poland's Unsound, Berlin's CTM, London's Cafe OTO and the UK retailer Boomkat all throwing their weight behind Nyege Nyege-approved singeli. Since Sounds Of Sisso, Nyege Nyege Tapes has deepened its focus on the genre, releasing several artist albums—Bamba Pana's Poaa, Jay Mitta's Tatizo Pesa and Duke's Uingizaji Hewa.

Nyege Nyege remains the key international conduit for singeli. They brought Bamba Pana and Makaveli to Jinja, Uganda, for the 2017 edition of the Nyege Nyege Festival. The following year, eight singeli artists made the 36-hour bus ride from Dar Es Salaam to Jinja for the festival, and this year's edition promises to have a strong singeli contingent. Sisso, Makaveli and Bamba Pana all performed at Unsound 2018 in Kraków, while MCZO and Duke were among the highlights of this year's CTM Festival in Berlin, playing a slot at Berghain between Indonesian duo Gabber Modus Operandi and Iranian experimentalist Sote.

Singeli artists have been embraced by European audiences, but for the likes of MCZO and Duke, young men with no formal education and who don't speak English, touring outside Tanzania brings with it challenges. MCZO's appearance at Unsound in 2018 was cancelled because of a spelling mistake in his passport. And last weekend, MCZO and Duke were refused entry to the United States, where they were scheduled to perform at Red Bull Music Festival in New York. In a statement, Duke and MCZO said that, despite an exhaustive visa application process, "nothing could prove that we did not intend to run away illegally... The [US] consular authorities seemed to sincerely think that there was a 'better life' available for us there, that we would not resist to chase."

Duke and MCZO in Berlin, January 2019

As singeli artists continue to travel internationally and soak up outside influences, it's possible the sound of singeli will evolve. It's a process that began at Nyege Nyege Festival, whose cosmopolitan lineup broadens the musical horizons of artists from East Africa, elsewhere on the continent and beyond. These musical exchanges are about to bear fruit, with Errorsmith and The Modern Institute remixes of singeli tracks set for release on Nyege Nyege Tapes this summer.

"The sound is constantly changing," said Arlen. "You have the slower, more twisted stuff that Duke is doing. They are also being exposed to music from further afield as they perform abroad. Also given all the different styles of electronic music in Dar Es Salaam, the singeli sound will inevitably mutate and evolve into something else at some point, like other genres mutated into singeli before."

When it arrived on the international stage, singeli "didn't compute with existing frames of reference of African electronic music," said Arlen. He noted some similarities to South Africa's Shangaan electro, a sound that was championed in Europe by Honest Jon's and later Warp Records, "but even that sounded softer than the frenetic sounds of singeli."

Kampire Bahana, a Kampala-based DJ and activist who works for Nyege Nyege Festival, first heard singeli when Arlen showed her a YouTube video. "At first it seemed unlike anything I'd ever heard before coming out of East Africa," she said. "The speed of the beat and the MCs delivery are very different from taraab and bongo flava and the other Tanzanian genres I was familiar with. Eventually I came to recognise the influence of other traditional and contemporary Tanzanian music in its sounds, but it still strikes me as a culture and sound all of its own, specific to the poor urban communities in Dar Es Salaam that birthed it." She said the singeli performances at Nyege Nyege Festival "were exactly the high energy, provocative acts that embody the festival's spirit."

Kampire said she felt a deeper kinship with singeli after watching the artist Nana "twerk furiously" during Sisso and Rehema Tahiri's performance during the last edition of Nyege Nyege Festival. "I felt an affinity for Tanzania," she said. "I think that both Uganda and Tanzania share the burden of a vocal and powerful moral fundamentalist bloc, but besides that there is liberatory culture and art being made that deserves just as much attention and support."

This moral fundamentalist bloc's full-throated rejection of a song last year saw Nyege Nyege make national news in Tanzania. The song, Rayvann's "Mwanza," sees bongo flava star Diamond Platnumz name-check Nyege Nyege. It was banned because in Swahili, "Nyege Nyege" translates to "horny horny." The song, which remains one of the most-played songs in Uganda, earned Diamond Platnumz a fine of nine million Tanzanian shillings—roughly £3000. "Diamond Platnumz argued that it was named after the festival in Uganda and was geared towards Ugandan fans, and that he would get booked at the festival because of the song," said Arlen.

Singeli artists have mostly operated outside the glare of Tanzania's oppressive government, but the prevailing political mood in the country is currently one of political and societal repression. Since he was elected in 2015, President John Pombe Magufuli, whose nickname is "the bulldozer," has taken aim at voices of opposition in politics and journalism, banning newspapers critical of his regime. A recent article by The Economist said he hates "critics, gay people and accurate statistics."

Dar Es Salaam is not always an easy place to have fun. I attended a block party in Mburahati, one week after seeing MCZO and Duke perform at the nightclub near the airport. Sisso had hired a massive sound rig that reverberated through the whole block. In order to get permission from the local authorities, Sisso needed a concrete reason for celebration. A cake marking the sixth birthday of Sisso Records did the trick.

The music started in the early afternoon. Some children hovered inquisitively by the decks, while others danced as Sisso played music from his laptop. Fairly soon, though, Sisso ran into some technical problems. He returned to his studio where he pulled out a screwdriver and pulled apart his laptop for emergency repairs. Eventually he left his laptop and brought his studio computer, monitor and all, outside to perform.

An hour later, the music was shut down. A couple of streets away a public funeral was taking place, with local councillors and police in attendance. This rendered the party's permit useless, and, following some tense conversations between police and Abbas, who is the scene's unofficial spokesman, it was agreed that they could hold the party the following day. By this time, I'd left to return to London, but Abbas told me the party was again thwarted by local police, with Jay Mitta arrested for reasons that never became clear.

One evening I sat with Abbas and Anti Virus (who goes by several other artist names, including Aunt Vairus and Aunty Virus) at Mamboz, a popular open-air restaurant in downtown Dar Es Salaam where diners sit at plastic chairs eating grilled chicken. She Bluetoothed me some of her music, including a killer tune called "Mahabuba." Anti Virus started MCing last year—before that she was a dancer and R&B singer. She's 19 and earns enough money to pay rent, but not much more. She told me she wants to perform singeli around the world. And when she becomes famous, she said she'd like to support up-and-coming musicians in Dar Es Salaam.

There aren't too many female MCs or producers in the singeli scene. Memoree Cad, who Kampire identified as one of East Africa's most promising electronic music artists, has a father in the military who takes a dim view toward her musical ambitions. Another promising female artist, Caad Reeda, has an upcoming split release on Nyege Nyege Tapes with Anti Virus.

After dinner at Mamboz, in Abbas's taxi, Abbas and Anti Virus engaged in an animated conversation as we drove through the downtown streets. Abbas translated the conversation to me. "I said to her, 'She doesn't have many role models, but I think with hard work and vision, she can make it.'"

Caad Reeda and Dogo Mjanja

Singeli lyrics are usually about everyday life—problems with money, problems with relationships, problems with authority. "The youth are complaining about things that piss them off—police corruption, the failure of the government to provide support in education, the lack of jobs and challenges of being young and being broke," said Abbas. "But a lot of singeli is also about having fun and partying."

In the case of one MC, the 15-year-old Dogo Mjanja, the lyrics skew more towards problems at school and with his parents. Dogo Mjanja, who has been MCing since he was 12, is a regular presence at the Sisso studio. One evening I stopped by to find Jay Mitta and Dogo Mjanja in the studio watching a final draft of the music video for "Tatizo Pesa," which would later appear on Jay Mitta's Tatizo Pesa album.

Outside, a group of women sat a couple of doors down, drinking beer, swapping stories and roaring with laughter. A truck full of plastic Coca-Cola crates kicked up dust as it drove down a nearby road. A man in his 20s called Pilo, who produces singeli videos, sat with Jay Mitta and Dogo Mjanja peering over his shoulder as he put the finishing touches on the clip, which was filmed the previous day around the corner from Sisso's studio, in a scrapyard filled with rusted-out buses and motorbikes.

Singeli's community of producers and MCs range in age from 15 to 50. At the other end of the scale from Dogo Mjanja is Rehema Tahiri, a woman in her 40s who got into singeli around 2016 and has become one of the scene's most exciting artists. A single mum who works multiple jobs to send her kids to school, Rehema MCs at singeli events around Tanzania, and performed at Nyege Nyege Festival in Uganda in 2018 and at Kenya's Africa Nouveau in 2019. Arlen first saw Rehema perform at a Nyege Nyege block party in Mburahati a few years back. "She rolled up and rocked it," he said.

"Singeli is local music," Rehema said. "Listen to those drums. It's young music—you can hear it in the way they dance and the way they sing."

The feature is supported by the British Council as part of their arts programming across sub-Saharan Africa.