UPSC CSE Prelims
Environmental Science & Technology Previous Year Questions (PYQs)
Showing solved Previous Year Questions for Chapter: Environmental Science & Technology
Topic Breakdown: Scroll →
With reference to Direct Air Capture, an emerging technology, which of the following statements is/are correct?
I. It can be used as a way of carbon sequestration. II. It can be a valuable approach for plastic production and in food processing. III. In aviation, it can be a source of carbon for combining with hydrogen to create synthetic low-carbon fuel.
Select the correct answer using the code given below.
Detailed Explanation:
Correct Answer: ✅ Option 3 (I, II and III)
Direct Air Capture (DAC) is an emerging technology that removes carbon dioxide (CO₂) directly from the atmosphere. The captured CO₂ can either be permanently stored underground (carbon sequestration) or utilized in various industrial applications, making it an important tool in climate change mitigation.
✅ Statement I is Correct: DAC can capture atmospheric CO₂ and store it permanently underground, helping in carbon sequestration.
✅ Statement II is Correct: Captured CO₂ can be used in the production of plastics, chemicals, beverages, and food processing industries.
✅ Statement III is Correct: In aviation, captured CO₂ can be combined with green hydrogen to produce synthetic low-carbon aviation fuels (e-fuels).
Short Notes: Direct Air Capture (DAC)
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DAC removes CO₂ directly from ambient air.
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It is considered a Negative Emission Technology (NET).
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Captured CO₂ can be stored underground or utilized industrially.
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DAC supports carbon sequestration and climate mitigation efforts.
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CO₂ from DAC can be used to manufacture plastics, chemicals, and synthetic fuels.
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Synthetic aviation fuels are produced by combining captured CO₂ with green hydrogen.
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Major challenges include high energy requirements and operational costs.
What is the role of ultraviolet (UV) radiation in the water purification systems?
- It inactivates /kills the harmful microorganisms in water.
- It removes all the undesirable odours from the water.
- It quickens the sedimentation of solid particles, removes turbidity and improves the clarity of the water.
Detailed Explanation:
✅ Statement 1 – Correct: UV radiation damages the DNA/RNA of microorganisms (bacteria, viruses, protozoa), effectively inactivating or killing them and making it a powerful disinfection method in water purification.
❌ Statement 2 – Incorrect: UV radiation does not remove odours from water; odour removal requires activated carbon filtration, aeration, or chemical treatment.
❌ Statement 3 – Incorrect: UV radiation does not affect sedimentation, turbidity removal, or water clarity; these processes require coagulation, flocculation, and filtration.
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