Network Updates / Africa / 2022-08-12

African cities turn to ‘green’:
buses in fight against pollution

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As rush hour dawns in Dar es Salaam, brightly coloured bajaji – or gas-powered rickshaws – deftly and opportunely squeeze through gaps between packed minibus taxis, known as dala dala.

Nearly half of the Tanzanian city’s 6.4 million residents rely on these vehicles, as well as a small bus rapid transit (BRT) fleet, as their primary mode of transportation. As these vehicles inch through congested streets and crowded urban spaces, they emit trails of soot that pose serious health risks to commuters and city dwellers. With urban populations in Africa set to increase by 2 billion people by 2050, experts say the problem will only get worse.

Through decarbonizing the transport sector and transitioning to cleaner buses, African cities can reduce environmental damage and human health risks while delivering a more reliable and speedy transport system to their growing urban populations, say experts.

The United Nations Environment Programme (UNEP) is helping African cities drive towards soot-free public transportation, including electric-powered buses. Building upon its successful campaign to eliminate leaded petrol and reduce sulfur levels in diesel fuels, UNEP has been developing strategic roadmaps and conducting readiness assessments to establish the groundwork for a low-carbon future for public transportation.

“Buses and trucks are a big source of harmful small particulate matter and black carbon, which is the second-most important short-lived climate pollutant,” says Jane Akumu, UNEP Programme Officer in the Sustainable Mobility Unit. “Vehicle fleets in a lot of the African cities are doubling every 10 years, so you can imagine the situation now – which is already bad – will get worse without action.

“Soot-free buses, low-sulfur fuels and cleaner vehicle technologies are the target because they would significantly reduce harmful emissions.”

Hazard warning

Approximately 95 per cent of the world’s transport energy still comes from fossil fuels. Sulfur levels in these fuels – particularly in diesel – mean that they form harmful particulate matter when burned, including black carbon, known as soot.

The health risks are stark.  Air pollution causes one in nine deaths, and nine out of 10 people breathe unclean air, according to the UNEP Pollution Dashboard. Burning fossil fuels also produces carbon dioxide, the main greenhouse gas that contributes to global warming and, in extension, myriad changes in our climate and natural systems.

Research shows that if humanity does not halve annual greenhouse gas emissions by 2030, it will be very difficult to limit global warming to 1.5 °C compared to pre-industrial levels by the end of the century. Based on current unconditional pledges to reduce emissions, the world is on a path to see global warming of 2.7 °C by the end of the century compared to pre-industrial levels.

Changing lanes


A white bus emitting black plumes of soot
Fossil fuel combustion produces outputs that harm both environmental and human health. Photo: Hyacinthe Nare


Many African cities’ formal public transportation systems have been unable to match the rapid growth of urban populations, ushering in a market for informal competitors, which eventually form the sector’s fabric.

“Public transport has failed… so people are now moving to two-wheelers, three-wheelers because they are more convenient and faster,” says Akumu. “It’s highly polluting.”

It is also not safe, says Akumu, noting that two- and three-wheelers account for many of the accidents in African cities.

In November 2021, UNEP, the Climate and Clean Air Coalition  (CCAC), and the African Association of Public Transport (UATP) held a workshop and launched key guidelines that establish a strategic roadmap designed to help African cities embrace electric mobility.

Response has been largely positive, according to the UATP, an association that works with governments on the development of public transport across 13 African countries.

“Governments in sub-Saharan Africa are receptive and fully support the transition to soot-free buses,” says Yssoufou Cisse, UATP Secretary General.

With UNEP and UATP support, the Executive Council of Urban Transport in Dakar (CETUD) conducted a cost-benefit analysis in 2021, which determined that expected revenue from full electric bus implementation on two of the city’s routes could ensure a return on investment within 10 years. Dakar’s public transport includes an express train, and the city is constructing a bus rapid transit system with electric vehicles.

“Public transport… is the most polluting form of transport because of the fleet constituted by old vehicles,” says Nancy Seck, a Transportation Engineer at Dakar’s Executive Council of Urban Transport. “Therefore, CETUD is putting in place a clean bus policy in order to reduce bus emission and improve air quality.”

Senegal has required the operator of the bus rapid transit system to use electric buses and has long-term plans to make feeder lines run on battery power as well.

UNEP and UATP had also previously supported an in-depth cost-benefit analysis in Lagos, Nigeria.


The primary challenges in the push to cleaner public transport are translating governments’ support into policy, ensuring adequate technical infrastructure needed to reconfigure public transport systems and securing funding, say experts.

While upfront costs for electric buses and other alternatives are relatively high, over the long term, governments are gradually accepting that they are more cost-effective, according to Akumu.

“If you do not buy or bring in clean technology vehicles, you’re going to spend more on health,” Akumu says. “We need to look at the overall cost of these poor-technology vehicles because, yes, they will be cheap – but there will be higher costs to be paid.”

In addition to improving environmental and human health, the introduction of soot-free buses must also address inefficiencies by serving a large number of citizens. While they may not spell the end for transport options like the bajaji or dala dala, soot-free buses should reduce reliance on informal public transport.

“Consumers are willing to pay slightly more for convenience, for comfort, for reliability,” says Akumu. “So, all those things need to be incorporated into this package.”

The long journey

The road to UNEP’s push for soot-free buses in Africa can be traced back to the 2002 World Summit on Sustainable Development in Johannesburg, where the Partnership for Clean Fuels and Vehicles (PCFV) was established.

Bolstered in 2012 by the establishment of the CCAC, UNEP ramped up its focus on cleaner transport. It began extensive efforts to transition to soot-free buses with African governments in 2016. Last year, UNEP also launched its Global Electric Mobility Programme,  which includes an Africa-specific component on electric-powered buses.

“Some cities in Africa, like Nairobi and Kampala, will be in a good position to introduce soot-free busses within their public transport operations within the next five years,” Cisse says. “With the imminent urbanization that will see the current urban population double by 2050, we have no choice but to pursue a soot-free future.”

For more information, please contact Althea Murimi [email protected]