UGC NET Questions (Paper – 1)

Non-point source pollution comes from many small, diffuse sources spread over a landscape rather than a single discharge point. Agricultural fields treated with fertilisers and pesticides generate runoff during rainfall that carries chemicals into streams and rivers, making it hard to attribute pollution to any one farm.

Option A:
Option A is correct because it involves numerous fields contributing pollutants in a widespread way, which is characteristic of non-point source pollution.

Option B:
Option B is incorrect since a factory outfall pipe is a classic point source with a clearly identifiable location and discharge.

Option C:
Option C is incorrect because a sewage treatment plant outlet is also a discrete point source, even if the effluent is inadequately treated.

Option D:
Option D is incorrect as a thermal power plant outfall is a specific, regulated point source, not diffuse pollution from many locations.

Statement D is the only wrong statement because eutrophication usually leads to algal blooms that can deplete dissolved oxygen and harm aquatic life rather than benefit it. Statements A, B and C correctly explain the process of eutrophication, the nature of point sources and examples of non-point sources such as agricultural runoff. Thus, identifying D only as the wrong statement matches the scientific understanding of water pollution and eutrophication.

Option A:
Option A is incorrect because it treats statement A as wrong, whereas A correctly defines eutrophication as nutrient enrichment causing excessive algal growth in water bodies. This phenomenon is widely recognised in limnology and environmental science. Misclassifying a correct definition as wrong makes this option invalid.

Option B:
Option B is correct because it pinpoints D as the single incorrect statement. Eutrophication tends to reduce oxygen levels through decomposition of algal biomass and can lead to fish kills and ecosystem degradation. Since A, B and C are accurate descriptions of relevant concepts, focusing on D only as wrong is logically consistent with the question.

Option C:
Option C is incorrect because it assumes both A and D are wrong. While D is indeed wrong, A is correct and supported by numerous environmental case studies on lakes and reservoirs. Including a correct statement in the set of wrong statements makes the combination unacceptable.

Option D:
Option D is incorrect because it groups C and D together as wrong statements. Although D is wrong, C is correct in identifying agricultural runoff and urban stormwater as typical non-point sources. Treating C as wrong contradicts standard classifications used in pollution control.