UPSC Prelims 2025 Q36: Environment & Ecology – Climate Change
- (a) I and II only
- (b) III only
- (c) I, II and III
- (d) None of the above statements is correct
Answer: (c) I, II and III
Explanation
Direct Air Capture (DAC) Applications:
| DAC Application | How It Works | Valid? |
|---|---|---|
| Carbon Sequestration (I) | Captures CO₂ from ambient air → stores permanently in geological formations | YES |
| Plastic Production (II) | Captured CO₂ → chemical feedstock → polymer/plastic manufacturing | YES |
| Food Processing (II) | CO₂ used for drink carbonation and modified-atmosphere food packaging | YES |
| Aviation Synthetic Fuel (III) | Captured CO₂ + green hydrogen → e-fuel (Sustainable Aviation Fuel) | YES |
Direct Air Capture (DAC): Technology that pulls CO₂ directly from ambient air using liquid solutions or solid chemical sorbents.
All three statements are correct — CO₂ captured can be stored permanently (I), converted to industrial feedstocks like plastics and food-grade CO₂ (II), or combined with green hydrogen to create synthetic aviation fuel (III).
Answer: (c) I, II and III.
Why each option is right or wrong
- (a) Incorrect. Statement III is also correct — CO₂ from DAC combined with green hydrogen produces synthetic aviation fuel (e-fuels/SAF), an active commercial pathway.
- (b) Incorrect. Statement III alone is too narrow. All three applications are scientifically proven and commercially explored.
- (c) CORRECT. All three statements describe real and validated DAC applications: permanent CO₂ storage (I), industrial feedstock for plastics and food (II), and synthetic aviation fuel synthesis (III).
- (d) Incorrect. DAC is commercially operational. All three described uses are accurate and recognized by IEA and IPCC.
Key point
DAC = captures CO₂ from ambient air. Three uses: (1) underground storage, (2) feedstock for plastics + food-grade CO₂, (3) e-fuels — CO₂ + green H₂ → synthetic aviation fuel.
Remember
DAC captures CO₂ from open air. Uses: store it, make plastics, carbonate drinks, or make aviation fuel with green H₂.
Common mistakes
- Thinking DAC is only for carbon storage and missing industrial applications like plastics, carbonated drinks, and aviation fuels.
- Confusing DAC (removes CO₂ from open air — anywhere) with CCS (captures CO₂ at emission source like a power plant). Different point of capture.
- Not knowing that Sustainable Aviation Fuel (SAF) can be produced by combining DAC-captured CO₂ with green hydrogen.
Exam tip
DAC vs CCS: DAC = remove CO₂ from open atmosphere. CCS = capture at emission source. Both reduce atmospheric CO₂ but at different stages. E-fuels use DAC output. UPSC increasingly tests negative-emission and carbon-removal technologies.
Sources
- IEA — Direct Air Capture Technology Report (2022)
- IPCC Sixth Assessment Report — Carbon Dioxide Removal Technologies
- Ministry of New and Renewable Energy — Carbon Capture Pathways