📘 IAS Prelims 2025 — GS-I Q.36 | Classroom Explanation

(Environment & Ecology | Climate Technology)

📌 Question

Q.36) 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.

(a) I and II only
(b) III only
(c) I, II and III
(d) None of the above statements is correct

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✅ Correct Answer: (c)

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🧑‍🏫 Classroom Explanation

This question tests understanding of negative emissions technologies (NETs), especially Direct Air Capture (DAC), a rapidly emerging area in climate mitigation with industrial, energy, and aviation linkages.

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🔍 Key Concept: What is Direct Air Capture (DAC)?

• DAC technologies capture CO₂ directly from ambient air
• Unlike point-source capture (power plants, factories), DAC:

• Can be located anywhere
• Targets existing atmospheric CO₂

• Captured CO₂ can be:

• Stored permanently (sequestration)
• Used as a resource (carbon utilisation)

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🔍 Statement-wise Analysis

✅ Statement I: Correct

• DAC removes CO₂ from the atmosphere
• When stored in:

• Deep geological formations
• Mineralised into rocks

→ It becomes carbon sequestration

• This qualifies as a negative emissions technology

➡️ Statement I is correct.

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✅ Statement II: Correct

• Captured CO₂ can be used as industrial feedstock, including:

• Plastics
• Carbon fibres
• Cement products

• In food processing:

• Beverage carbonation
• Food preservation

• This locks carbon into products and infrastructure, delaying its return to the atmosphere

➡️ Statement II is correct.

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✅ Statement III: Correct

• DAC-derived CO₂ can be combined with green hydrogen to produce:

• Synthetic fuels (e-fuels)

• Aviation application:

• CO₂ + H₂ → synthetic jet fuel
• Known as Power-to-Liquid (PtL) pathway

• Especially important because aviation is:

• Hard to electrify
• Dependent on liquid fuels

➡️ Statement III is correct.

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🔗 Integrated Understanding (UPSC Core)

• DAC supports:

• Climate mitigation (sequestration)
• Circular carbon economy (utilisation)
• Hard-to-abate sectors (aviation)

➡️ All three statements are correct.

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🧮 Logical Elimination (UPSC Style)

• I → Correct
• II → Correct
• III → Correct

➡️ Correct option: (c)

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🎯 Final Answer

✅ Correct Answer: (c) I, II and III

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📦 Info Box — Extra Points (Prelims Value Add)

• DAC challenges:

• High energy requirement
• High cost per tonne of CO₂

• DAC vs CCS:

• DAC → captures CO₂ from air
• CCS → captures CO₂ at emission source

• Key DAC applications:

• Net-zero strategies
• Aviation decarbonisation
• Carbon-neutral fuels

• UPSC Trap Alert:

• DAC ≠ only storage
• Utilisation pathways are equally important

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📍 GS Mapping

GS Paper III
Theme: Environment, Climate Change
Topic: Climate Mitigation Technologies
Nature: Conceptual + Applied Science

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