City of Johannesburg investigates mysterious sulphur-like smell as complaints surge

The City of Johannesburg has confirmed that it is probing the origins of a a sulphur-like stench in parts of Sandton and surrounding suburbs.

The Environment and Infrastructure Services Department (EISD) has addressed numerous complaints about a strong odour spreading across several areas of the city.

This comes as reports have indicated that residents in areas such as Sandton, Randburg, Roodepoort, Fourways, and Parktown reported this stark, pungent smell, perceived initially as sulphur-related, on January 16, 2026.

The city's spokesperson, Nthatisi Modingoane said the sheer volume of reports led the City to launch an immediate investigation. "Upon further investigation, the City determined that the odour, often described as resembling “rotten eggs,” is more closely associated with hydrogen sulphide (H₂S). This finding set the stage for a deeper inquiry into the origin of the smell."

"Field surveys carried out by City officials confirmed that the odour was indeed widespread and not limited to a specific area, suggesting a non-localised pollution source. Given the geographical spread of complaints coupled with current meteorological conditions, experts suggest that the residents were likely affected by a transboundary pollution source," Modingoane said.

It is also reported that the stench can be attributed to the recent weather patterns, which appear to have facilitated the long-range transport of air pollutants originating from the Highveld Priority Area and industrial operations in Mpumalanga Province, which encompass power generation and petrochemical activities. The characteristics of the reported odour align with typical emissions from these processes.

"Interestingly, this isn't the first occurrence of sulphur-related odours permeating Johannesburg. Over the past five years, the City has experienced similar phenomena intermittently, particularly between January and March. This timeframe is known for atmospheric conditions that favour extended pollutant transport, leading to increased vigilance from City officials," the city said.

In response to these incidents, Johannesburg has invested in hydrogen sulphide monitoring instruments, now stationed at the Buccleuch and Alexandra air quality monitoring stations, to track elevated H₂S levels.

Modingoane further highlighted that the city does not host major heavy industrial activities; all industrial operations within Johannesburg are licensed and monitored by the Environmental Management Inspectorate to ensure compliance with environmental laws.

"Nevertheless, the current situation urges precautionary measures: residents are advised to stay indoors when faced with strong sulphur-like odours and to moderate outdoor exertion," he added.

Particularly at risk are vulnerable groups, including the elderly and children, who should be closely monitored for any signs of discomfort, such as eye and throat irritation, headaches, dizziness, and fatigue. Continuous exposure could lead to more serious health implications, including respiratory complications and neurological disruptions.

Modingoane further stressed that the EISD Air Quality Management Unit is committed to collaborating with other governmental bodies to pinpoint the exact source of the odour. Monitoring of complaints will intensify in the days ahead, particularly as weather conditions improve, which is expected to aid in the dispersion of any lingering pollutants.