31 October: carbon capture (CCUS)
Saturday 31 October 2026
GS Paper 3 · 150 words · 10 marks
What is Carbon Capture, Utilization and Storage (CCUS)? What is the potential role of CCUS in tackling climate change?
(UPSC Mains 2025, GS Paper 3, Q7)
You have seven minutes. Write your answer before you read anything below.
Open only after you have written
How to approach this question
The directive. There is no directive word. Answer the two questions in order. Potential role invites a judgement, so include the limits.
A shape that works in 150 words.
| Part | Words | What to write |
|---|---|---|
| Definition | 25 | What CCUS is, in one or two lines |
| How it works | 30 | Capture, use, storage |
| Its role | 50 | Where it helps, with named evidence |
| Its limits | 25 | Cost, scale, fossil lock-in |
| Conclusion | 20 | Where it should be used |
Material you can use.
| Item | Detail |
|---|---|
| Uses of captured CO2 | Urea, chemicals, building materials |
| Storage sites | Depleted oil and gas fields, deep saline formations |
| Hard-to-abate sectors | Cement (CO2 from limestone), steel |
| IPCC | 2022 mitigation report includes carbon capture in 1.5°C pathways |
| Sleipner, Norway | CO2 stored under the North Sea since 1996 |
| India | Net zero target 2070. NITI Aayog CCUS policy report, 2022 |
Mistakes to avoid.
| Mistake | What to do instead |
|---|---|
| Spending half the answer on the definition | Two lines, then the role |
| Only benefits | Add cost and scale, then judge |
| Treating CCUS as a reason to keep building coal plants | Say where it fits and where it does not |
A model answer
Carbon capture, utilisation and storage (CCUS) traps carbon dioxide at large sources, such as power plants and cement kilns. The gas is then used or stored underground.
How it works. CO2 is separated from exhaust gas and compressed. It can make urea or building materials, or be injected into depleted oil fields or deep saline rock.
Its role.
- Cement releases CO2 from limestone, so clean power alone cannot remove it.
- The IPCC's 2022 mitigation report includes carbon capture in pathways that limit warming to 1.5°C.
- Norway's Sleipner project has stored CO2 under the North Sea since 1996.
- NITI Aayog's 2022 report sees CCUS as necessary for India's 2070 net zero target.
Its limits. It is costly and energy-hungry, and can prolong coal use. Global capacity is small next to emissions.
CCUS should be kept for sectors with no cleaner option, and paired with a carbon price to fund it.
Word count: 149.
| Where | What earns credit |
|---|---|
| Opening | A definition in two lines |
| Body | Role and limits, each with named evidence |
| Conclusion | Says where CCUS fits |