(๐) Heavy suspended particles might be floating in the water served for drinking.
(๐๐) Water could have been made fit for drinking by adding alum to the water. The heavy particles of dissolved alum deposit on the finer suspended particles. The suspended particles become heavy and settle down at the bottom of the tank. This process is known as sedimentation.
(๐๐๐) Ignorance, carelessness, unhygienic conditions.