Indiscriminate use of water by increasing population and industrial expansion has led degradation of the quality of water considerably. Surface water available from rivers, canals, lakes, etc. is never pure. It contains small quantities of suspended particles, organic and inorganic substances. When the concentration of these substances increases, the water becomes polluted and hence becomes unfit for use. In such a situation, the self-purifying capacity of water is unable to purify the water.

Which of the following is not a natural source from which water pollutant is created?

Cultural activities

Though water pollutants are also created from natural sources (erosion, landslides, decay and decomposition of plants and animals, etc.) pollutants from human activities are the real causes of concern. Human beings pollute the water through industrial, agricultural and cultural activities. Among these activities, the industry is the most significant contributor.