Plastic bags, bottles, foam containers and household waste have been washed ashore and trapped along embankments and riverbanks in several sections of the river.
Residents said the problem has persisted for years and tends to worsen after periods of heavy rainfall, when waste from upstream areas is carried downstream into the urban centre.
Local authorities said tidal movements also contribute to the accumulation of waste along the river.
To address the issue, authorities have asked environmental service providers to increase waste collection efforts on the river.
Waste collection boats now operate twice daily along the river, while efforts to curb illegal dumping include public awareness campaigns and the installation of surveillance cameras.