The Ministry of Water and Environment has explained the source of the foul smell affecting parts of Lake Victoria, especially Inner Murchison Bay in Kampala and sections of Entebbe, saying it is caused by the decay of algal blooms linked to rising pollution and high nutrient levels in the lake.
In a statement released today, the ministry said Lake Victoria and its basin support more than 45 million people across the region, providing water for drinking, transport, hydropower and livelihoods, while also hosting key ecosystems and economic activity. However, the most heavily used bays in Uganda, including Inner Murchison Bay, Kitubulu and Nakiwogo in Entebbe, are now under increasing environmental pressure.
Officials say these bays receive heavy pollution loads from surface runoff carrying silt, plastic and human waste, municipal sewage from surrounding suburbs, industrial effluent and runoff from agricultural fields. The situation has been worsened by the degradation of wetlands that previously filtered waste and trapped nutrients before water flowed into the open lake.
According to the ministry’s Water Quality Monitoring Network, which operates 23 monitoring stations in Inner Murchison Bay and 10 in Entebbe Bay, nutrient levels of nitrogen and phosphorus have continued to rise. These nutrients fuel rapid algal growth. When the algae die and decompose, they consume oxygen in the water and release gases such as hydrogen sulphide and ammonia, producing the strong, unpleasant smell reported by residents.
The ministry says the stench has been more severe in recent weeks due to dry weather and higher temperatures, which have accelerated the decomposition process. The low oxygen levels associated with the decay also pose a risk to aquatic life and could lead to fish kills.
To address the problem, government says it is restoring degraded wetlands around the lake and its catchment areas to improve natural filtration of waste before it enters the lake. Authorities have also prioritised enforcement of a 200-metre buffer zone around Lake Victoria to intercept pollutants and protect the shoreline.
Regular water quality monitoring is continuing to guide policy and response measures, while industries within the lake’s catchment are being encouraged to adopt cleaner production methods, recycle and reuse wastewater, and reduce the volume of effluent discharged into the environment.
The ministry has urged communities, local authorities and businesses around Lake Victoria to play their part in reducing pollution, warning that without sustained action, the foul smell and ecological damage in the lake’s bays could become more frequent and severe.