UPSC Prelims Marathon 9 August – Environmental Pollution – 2 – 2025

Consider the following statements regarding Sulphur Dioxide (SO₂) emissions:
1.Ships and locomotives using fossil fuels are the primary sources of SO₂ emissions globally.
2.Extraction and processing of metal ores release significant amounts of SO₂.
3.Fossil fuel-based power plants are the largest contributors to SO₂ emissions, as per the Environmental Protection Agency (EPA).
Which of the above statements is/are correct?

Consider the following statements regarding Biochar:
1.Biochar is produced by heating agricultural and organic waste at high temperatures in the presence of oxygen.
2.Biochar application in agriculture can help reduce nitrous oxide emissions and improve water retention in nutrient-poor soils.
3.In the construction sector, biochar can serve as a carbon sink by being integrated into building materials.
Which of the above statements is/are correct?

Hydrofluorocarbons (HFCs) are used in which of the following applications?
1.As propellants in aerosol products
2.As blowing agents in foam manufacturing
3.As fire suppression agents
4.As refrigerants and lubricants in cooling systems
How many of the above applications involve the use of HFCs?

Consider the following statements regarding Mercury Pollution:
1.Mercury emitted into the atmosphere can travel long distances across continents before settling back to the earth.
2.Methylmercury is primarily formed in the human body through digestion of elemental mercury.
3.Artisanal and small-scale gold mining is the largest source of anthropogenic mercury emissions globally.
4.Natural re-emission of mercury from land and water surfaces contributes to the current levels of atmospheric mercury.
How many of the above statements are correct?

Consider the following statements regarding plastic pellets (nurdles):
1.Nurdles are microplastic raw materials used in plastic manufacturing processes such as moulding and extrusion.
2.Nurdle pollution primarily results from public littering along coastlines.
Which of the above statements is/are correct?

Which of the following are classified as secondary air pollutants?
1.Tropospheric Ozone (O₃)
2.Sulfur dioxide (SO₂)
3.Ammonium Sulphate
4.Photochemical Smog
5.Carbon monoxide (CO)
Select the correct answer using the code given below:

According to the WHO Air Quality Guidelines and general understanding of air pollutants, consider the following statements:
1. The 24-hour mean concentration of PM2.5 should not exceed 15 µg/m³, and the annual mean should not exceed 5 µg/m³.
2. The highest levels of ozone pollution are generally observed during cloudy and rainy weather conditions.
3. Excessive ozone in the air can act as a trigger for asthma attacks.
Which of the above statements are correct?

Consider the following statements regarding Flue Gas Desulphurisation (FGD):
1.FGD is a pollution control technology used to remove sulfur dioxide from flue gases emitted primarily by coal-based thermal power plants.
2.Flue gas contains only carbon dioxide and water vapour and is considered non-polluting.
3.Sulphur dioxide in flue gas contributes to both particulate matter pollution and respiratory illnesses.
Which of the above statements is/are correct?