what is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.

• Sewage is the wastewater containing both liquid and solid wastes produced by human activities from homes, industries, hospitals, offices, etc.
• Sewage contains various contaminants including disease-causing bacteria and other microbes.
• If untreated sewage is discharged into rivers or seas, then the water in the rivers or seas would also get contaminated.
• If this contaminated water is used for drinking, then it can cause diseases such as cholera, typhoid, dysentery, etc. which may lead to death.
• That is why it is harmful to discharge untreated sewage into rivers or seas.