Calls for ‘clean air zones’ to tackle pollution by old cars

Calls are growing stronger for action to tackle vehicle pollution in Johannesburg after a new study found people living in the city’s central and southern areas are exposed to the highest levels of harmful emissions.

The study conducted by the University of Johannesburg’s process, energy & environment technology station (UJ Peets) and the International Council on Clean Transportation (ICCT), found a small number of older vehicles are responsible for a disproportionate amount of pollution.

Researchers collected more than 250,000 vehicle exhaust measurements across the city between July and September 2025 in Africa’s real-world roadside vehicle emissions study. The report found petrol passenger cars registered before 2006 make up only 4% of the city’s vehicle fleet but contribute up to 24% of measured emissions.

It also found older petrol minibus taxis emit far higher levels of pollution than newer vehicles, while newer diesel minibuses produce significantly higher particulate matter and nitrogen oxide emissions than petrol taxis.

Researchers estimated transport-related emissions were linked to about 500 premature deaths and 200 new childhood asthma cases in Johannesburg in 2024. Residents in central and southern Johannesburg, where many people rely on public transport, were found to face the highest exposure to vehicle emissions.

The study recommends introducing clean air zones (CAZs), adopting stricter vehicle emission standards, expanding and enforcing Johannesburg’s vehicle inspection and maintenance programme, and supporting the shift to electric minibus taxis through financing schemes.

Mallery Crowe, associate co-author of the report, said: “Worldwide evidence shows a phased approach to clean air zone implementation works well for cities seeking to reduce transport emissions, starting with targeted measures before building toward broader restrictions.”

She said Johannesburg should start in the central and southern parts of the city, where pollution levels are highest. She proposed an expansion of electric bus services and helping the taxi industry move to electric vehicles.

“For Johannesburg, practical first steps could include prioritising vehicle emission-focused CAZs in the central and southern parts of the city, where our data shows overall vehicle emissions are highest and residents are most exposed. Within these zones, expanding electric bus routes and supporting the transition to electric minibus taxi alternatives would reduce emissions while lowering lifetime operating costs for operators.”

Crowe said stronger enforcement of vehicle inspections would help identify the biggest polluters. “The The Real World Urban Emissions (True) Initiative has identified the expansion and enforcement of Johannesburg’s existing vehicle inspection and maintenance programme as a key solution for identifying high emitters and reducing real-world emissions in the urban centre,” she said.

“Prioritising older and larger commercial fleets would have outsized benefits, as petrol light commercial vehicles and minibus taxis registered before 2006 made up only 3% to 8% of their respective fleets yet contributed 13% to 22% of overall HC emissions and 20% to 25% of CO² emissions.”

The Automobile Association (AA) backed efforts to reduce emissions, saying safer, roadworthy vehicles should be part of the solution. “We welcome the findings of the True Initiative, which shows the different levels of exposure to vehicle emissions and air pollution across the City of Johannesburg,” said AA CEO Bobby Ramagwede.

He said the organisation continued to call for compulsory annual roadworthiness tests linked to licence disc renewals. “Alongside these findings, we believe roadworthy vehicles can only aid in the fight for lower emissions, hence the AA’s call for annual roadworthiness tests to be made compulsory.

“These tests would be tied to a motorist’s car licence disc renewal application, and would make for heathier vehicles on our roads, healthier emissions and ultimately a greener pollution landscape.”

Ramagwede said driver behaviour and poor road infrastructure also contribute to higher emissions.

“Driver behaviour becomes another factor in the race towards greener emissions. We believe that frameworks such as the K53 are outdated and in need of revision, with affordable modern driver training becoming very necessary to educate today’s motorist on how to navigate economical and lower-emission driver habits.

“Road conditions also play a part in greener-emission mobility. Congestion caused by poor infrastructure and unnecessary traffic leads to additional mileage and additional carbon emissions into our environment.”

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