Chapter 18 of NCERT Solutions for Class 7 Science focuses on pollutants' concerns with natural resource water and its grave effects. It discusses how pollution is created and how it affects people's health. The conversion of wastewater created by human activities, which results in soil and water contamination, is also covered in this chapter. The construction of a wastewater treatment plant to minimise pollution levels in the environment. Adoption and installation of low-cost on-site sanitation solutions to replace sewage systems that are unavailable. The Wastewater Treatment Plant's by-products, on the other hand, include Biogas and Sludges.