Concept:
- The case is strongest when it is built around who suffers, because the harm from polluted water spreads far beyond the factory that caused it.
- Four groups are affected in turn: the river, the people, the farmer and the industry itself.
Step 1: The river suffers first.
Paper, pulp, chemical, textile and dyeing units, refineries, tanneries and electroplating plants pour dyes, acids, salts, heavy metals such as lead and mercury, pesticides and synthetic chemicals into flowing water.
Hot water released by factories and thermal power plants adds thermal pollution, which cuts the oxygen in the water and kills aquatic life.
Step 2: People downstream suffer next.
Villages and towns that draw drinking water from the same river receive the waste of the factories upstream. Heavy metals do not break down and build up in the body over the years, causing lasting illness.
Fly ash, phospho-gypsum and slag dumped on land seep down and contaminate the wells as well.
Step 3: Farmers suffer through the soil.
Irrigating fields with polluted water carries chemicals into the soil, damages fertility and leaves residues in the crop itself. A farmer can lose a season, and a soil once loaded with salts and metals takes years to recover.
Step 4: Industry ends up harming itself.
Factories need large volumes of clean water to run. When the nearby source is spoiled and the water table falls from over-extraction, industry has to bring water from farther away or treat it at heavy cost.
Pollution therefore raises the cost of production for the very units that caused it.
Step 5: What can be done instead.
Water use can be minimised by reusing and recycling it in two or more successive stages, rainwater can be harvested to meet part of the demand, and effluents can be treated in three phases, mechanical, biological and chemical, before being let out.
Ground water recharge and legal control over overdrawing complete the effort.
Final Answer: Industrial pollution harms the river, the people who drink from it, the farmer who irrigates with it and finally the industry that depends on it. Since workable remedies exist, saving clean water from industrial pollution is both necessary and possible.