By Daniel in Health

How Bad Is South Africa's Air Quality, Really?

On a still winter morning Johannesburg has ranked as the most polluted big city on earth. Here's what's driving it, who pays the price, and what you can do.

If you've ever stood on a Johannesburg balcony on a still June morning and noticed the horizon looks like it's been rubbed with a dirty eraser, that's not your imagination. On the 31st of May this year, IQAir's live rankings briefly put Johannesburg at the top of the list, ahead of Lahore, Delhi and Kinshasa, as the most polluted major city in the world at that hour.^[1] It didn't stay there; air quality swings hour to hour, but it's not a one-off. Winter after winter, the same haze settles over Gauteng and Mpumalanga, and most people just call it "highveld weather" and get on with their day.

It's worth pulling that apart properly, because South Africa's air quality problem is bigger, older and more unevenly distributed than a single bad headline suggests.

The numbers behind the haze

Johannesburg's annual average PM2.5 concentration for 2025 came in at 17.1 micrograms per cubic metre.^[1] That sounds abstract until you compare it to the benchmark: the World Health Organization's guideline for safe annual exposure is 5 micrograms per cubic metre. So on an average day, not even a bad one, Joburg's air carries more than three times the fine particulate matter the WHO considers safe to breathe long term, year in and year out.

And Johannesburg isn't even the worst of it. East of the city, in the industrial belt that stretches through Mpumalanga, sits the Highveld Priority Area, a stretch of roughly 31,000 square kilometres declared a national pollution hotspot back in 2007. It's home to a cluster of Eskom's coal-fired power stations, Sasol's Secunda coal-to-liquid plant (the only one of its kind in the world), plus coal mines, steel smelters and chemical plants, all sitting more or less on top of each other.^[2] In March this year, monitors in eMalahleni recorded a daily PM2.5 reading of 187 micrograms per cubic metre, more than 12 times the WHO's 24-hour guideline of 15 micrograms per cubic metre. Sulphur dioxide near Secunda hit 370 parts per billion in early 2026, against a national standard of 48.^[2]

A 2019 Greenpeace analysis ranked the Highveld among the worst places on the planet for nitrogen dioxide and sulphur dioxide emissions, not just the worst in South Africa.^[3] That ranking is now several years old, but little about the underlying industry footprint has changed since.

Why winter makes it so much worse

Pollution doesn't spike randomly. In winter, the Highveld gets cold, dry and still, and temperature inversions trap a layer of cool air, and everything in it, close to the ground instead of letting it rise and disperse. At the same time, more people are burning coal and wood to heat their homes, veld fires pick up, and the whole region effectively puts a lid on itself for a few months. That's why weather reports mentioning "hazy conditions expected over Gauteng" every May and June aren't being dramatic; they're describing a real seasonal pattern. Spring's warmer air and stronger winds are usually what finally clears it, not any change in what's being pumped into the sky.

Who actually pays for it

This isn't just an inconvenience for people who enjoy a clear view of the sky. Research from the South African Medical Research Council has linked pollutants like PM10 and sulphur dioxide in the Highveld to higher rates of tuberculosis, asthma, sinus disease and general respiratory illness, along with elevated cardiovascular risk.^[4] A study of adolescents living in the Highveld Priority Area found measurably worse respiratory health than in comparison areas.^[5] Nationally, air pollution was linked to an estimated 25,800 premature deaths in South Africa in 2019 alone, making it the country's second largest health risk. Nearly every South African breathes air that exceeds WHO guideline levels at some point.^[4]

The burden isn't spread evenly either. Communities that live closest to the power stations and refineries, often lower income and with the least ability to relocate, carry the heaviest exposure. Add household air pollution on top of that: many families in these areas still cook and heat with coal, wood or paraffin, and indoor PM2.5 levels in those homes have been measured higher than the polluted air outside.

It's serious enough that in 2022 South Africa's High Court ruled, in what's become known as the "Deadly Air" case, that the state of the air in the Highveld breaches residents' constitutional right to an environment that isn't harmful to their health. The environment minister appealed, and lost: in April 2025 the Supreme Court of Appeal dismissed that appeal and gave the minister twelve months to publish enforceable regulations giving effect to the Highveld air quality plan.^[6] That deadline fell in April 2026. Government's own Highveld Priority Area plan now targets a 40% cut in emissions by 2030, but environmental groups like groundWork argue that emissions exemptions already handed to Eskom and Sasol make that target close to unreachable as things stand, and Sasol itself has pushed back on the idea that the target applies to each of its facilities individually rather than the industry as a whole.^[2]

What you can actually do about it

You can't fix a coal power station from your living room, but you can reduce how much of this you and your family breathe in.

Check before you commit to an outdoor run. The government's own SAAQIS platform (saaqis.environment.gov.za) pulls real-time readings from a national network of more than 130 government-run monitoring stations, plus dozens of private ones, and there's a free app for it.^[7] IQAir's website and app cover the same ground with easier-to-read colour ratings. On a bad air day, especially in Gauteng or Mpumalanga in winter, push the gym session or the jog indoors.

Mind the indoor air too. If your household burns coal, wood or paraffin for heating or cooking, make sure the room is properly ventilated. Studies in South African townships have repeatedly found indoor pollution levels higher than what's outside, precisely because a closed room traps smoke that would otherwise disperse.

Keep windows shut on inversion mornings and open them once the haze lifts, usually by mid to late morning once the sun has warmed the air enough to break the inversion.

If you or your children have asthma, TB history or heart conditions, treat high-AQI days the way you'd treat a pollen warning: keep reliever medication on hand, limit exertion outdoors, and speak to a doctor about a mask if you live in or near the Highveld belt.

None of this fixes the underlying problem. That requires power stations that actually meet emissions standards, a coal-to-liquid industry that either cleans up or winds down, and a state willing to enforce its own court orders. But knowing what's actually in the air you're breathing, and on which days it's worse, is the one piece of this you can act on today.