If you live anywhere in Joburg or Mpumalanga, you might have gotten a whiff of a terrible smell in the past few days. It smells a lot like rotten eggs. Ew, right? But that’s actually the smell of sulphur dioxide and hydrogen sulphide. The Gauteng Weather service even issued a warning about poor air quality in Gauteng on Wednesday, followed by a tweet saying that the Department of Environmental Affairs would be investigating the root cause of the stench. Sasol was believed to be the first culprit responsible for the stench. The energy and chemical company’s plant in Mpumalanga was said to be emitting elevated levels of sulphur dioxide and hydrogen sulphide in the air, the South African reported. But further digging by Business Maverick showed that the investigation was still ongoing by both the department and Sasol itself. Sasol told Business Maverick that its emissions profile is compliant its and operations are stable, adding that “abnormal atmospheric conditions” are compounding the effects of the industrial sulphur emissions in the Mpumalanga Highveld and Gauteng regions. We don’t know how long it will be in the air, but at least you have a mask to protect you from the stench. Another reason to keep it on.