The City of Johannesburg says it is investigating a strong sulphur-like smell that has been reported by residents in several areas.
People living in Sandton, Randburg, Roodepoort, Fourways, and other nearby areas first noticed the smell on 16 January 2026. The odour was reported again on 9 March.
The City’s Environment and Infrastructure Services Department (EISD) started an investigation after receiving complaints from residents.
City Manager Dr Floyd Brink says protecting residents’ health remains the City’s priority.
He says teams are monitoring air quality and working with national and provincial government departments to find the source of the smell.
According to the City, recent weather conditions in Johannesburg — including warm temperatures, humidity and occasional rain — can sometimes trap pollutants in the air and cause strong odours.
Air quality monitoring stations in Buccleuch and Alexandra detected higher levels of hydrogen sulphide, a gas that is known for its rotten-egg smell.
The City says the gas reached levels of about 36 to 37 parts per billion at the Alexandra monitoring station. Levels of sulphur dioxide were also recorded at about 52 parts per billion.
Despite these spikes, officials say the pollution levels remain relatively low and are not expected to pose serious health risks. However, the levels are strong enough for people to notice the smell.
Hydrogen sulphide is commonly associated with industrial activities and can sometimes travel long distances in the air.
The City says the smell may be linked to industrial emissions from the Highveld region, which is known for heavy industry and power stations. Because the pollution may come from outside Johannesburg, the matter has been referred to the National Department of Forestry, Fisheries and the Environment and the Gauteng Department of Environment.
Officials say Johannesburg itself does not have major heavy industrial operations. Industries operating in the city are licensed and regularly monitored to ensure they follow environmental laws.
As a precaution, the City has advised residents to stay indoors when the smell is strong and avoid strenuous outdoor activities.
People who are elderly, children, or those with respiratory problems should be monitored for symptoms such as eye or throat irritation, headaches, dizziness or fatigue.
The City says it will continue monitoring air quality and analysing weather patterns to determine where the smell is coming from.
Residents can also check air quality updates on the South African Air Quality Information System (SAAQIS).
The City says it will provide further updates once more information becomes available.
