Concept:Pollution refers to the introduction of harmful or untreated substances into the environment.
Explanation:Treated sewage is passed through treatment processes that remove harmful materials and pathogens.
As a result, releasing treated sewage is far less likely to cause pollution compared with the other options.
Industrial waste often contains toxic chemicals and heavy metals that contaminate water and soil.
Oil spillage coats water surfaces, harms aquatic life, and damages ecosystems.
Fishing with chemicals introduces poisons into water bodies, killing fish and disrupting the food chain.
Among the given choices, only treated sewage does not directly cause pollution under normal conditions.
Therefore, treated sewage is the correct exception.
Answer:A. treated sewage