1. India stood third globally in total renewable energy installed capacity as of December 2025.
2. India surpassed Germany to enter the top three global renewable energy leaders.
3. India’s total renewable energy installed capacity, as cited in the global ranking, was above 250 GW.
Which of the statements given above are correct?
Core Concept: The question tests the distinction between global renewable energy ranking and the specific country displaced by India. India moved to third position globally by surpassing Brazil, not Germany. The installed renewable energy capacity cited in the ranking was 250.52 GW.
Option (a) – Incorrect: Statement 1 is correct because India was ranked third globally as of December 2025. However, Statement 2 is incorrect because India surpassed Brazil, not Germany, to enter the top three.
Option (b) – Correct: Statement 1 is correct as India officially secured the third global position. Statement 3 is also correct because the cited installed capacity was 250.52 GW, which is above 250 GW.
Option (c) – Incorrect: Statement 2 is incorrect because Germany was not the country displaced by India from the top three. Statement 3 is correct, but this combination misses Statement 1, which is also correct.
Option (d) – Incorrect: This is a trap option because two statements are correct, but Statement 2 is factually wrong. UPSC often places one wrongly identified country or institution to make an otherwise attractive option incorrect.
1. India achieved the target of having 50% of its cumulative electric power capacity from non-fossil sources ahead of schedule.
2. This achievement means that non-fossil sources now account for more than half of India’s total annual electricity generation.
3. This milestone is distinct from the target of reaching 500 GW of non-fossil capacity by 2030.
Which of the statements given above are correct?
Core Concept: The question tests the distinction between installed capacity, actual electricity generation, and future capacity targets. A milestone in cumulative installed capacity does not automatically imply a corresponding share in annual generation.
Statement 1 – Correct: India attained the milestone of 50% cumulative electric power capacity from non-fossil sources ahead of the 2030 timeline. This is an installed-capacity milestone.
Statement 2 – Incorrect: Cumulative installed capacity and actual annual electricity generation are different indicators. A higher share in installed capacity does not automatically mean that more than half of annual electricity generation comes from non-fossil sources.
Statement 3 – Correct: The 50% cumulative capacity milestone is separate from the broader target of reaching 500 GW of non-fossil capacity by 2030. One refers to share in total capacity, while the other refers to absolute capacity addition.
Option (a) – Incorrect: This describes utility-scale solar expansion and grid infrastructure, which is different from a household rooftop solar programme.
Option (b) – Correct: PM Surya Ghar is designed to promote rooftop solar adoption at the household level, making it a decentralised clean energy initiative with direct consumer participation.
Option (c) – Incorrect: This describes the purpose of the National Green Hydrogen Mission, not PM Surya Ghar. The trap lies in mixing two different clean-energy initiatives.
Option (d) – Incorrect: This option introduces an unrelated policy objective. PM Surya Ghar is not designed around replacing large hydropower or promoting decentralized bioenergy systems.
1. It involves encoding and transmitting information between distant quantum systems.
2. It primarily relies on single photons to encode information.
3. In Quantum Key Distribution, interception of the transmitted key can in principle be detected.
Which of the statements given above are correct?
Core Concept: Quantum communication uses quantum states, typically of light, to transmit information securely between distant systems. Its best-known application is Quantum Key Distribution, in which the act of observation disturbs the quantum state, making eavesdropping detectable.
Statement 1 – Correct: Quantum communication is concerned with encoding and transmitting information between distant quantum systems. This distinguishes it from merely improving classical encryption over conventional channels.
Statement 2 – Correct: Like classical optical communication, quantum communication uses light as the carrier, but here information is encoded in quantum states, often through single photons. The emphasis is on quantum properties, not just optical transmission.
Statement 3 – Correct: In QKD, any attempt to intercept or observe the key alters the quantum state involved. This makes the communication intrinsically tamper-evident, which is the core security feature of the system.
Core Concept: Quantum Key Distribution is not about transmitting ordinary messages faster or boosting signal strength. Its importance lies in securely generating and sharing encryption keys using quantum states, so that any interception attempt becomes detectable.
Option (a) – Incorrect: Signal amplification is a telecommunications function, not the defining role of QKD. In fact, the validation here emphasized secure key generation over links without signal amplification.
Option (b) – Correct: QKD uses quantum states of light to share secret keys. Because observation disturbs the quantum state, any eavesdropping attempt can be detected by the communicating parties.
Option (c) – Incorrect: Quantum communication does not imply faster-than-light information transfer. This is a common conceptual trap arising from confusion around entanglement and quantum mechanics.
Option (d) – Incorrect: Superconducting materials are associated with broader quantum technologies, but QKD itself is a communication and key-sharing method, not a storage mechanism for encrypted messages.
Reason (R): The demonstrated network used existing fiber cables, while the broader mission also includes free-space and satellite-based communication pathways.
Core Concept: A major challenge in quantum communication is practical deployment at scale. The importance of this achievement lies not only in secure transmission, but also in the fact that it was built over existing telecom fiber, showing compatibility with scalable real-world infrastructure. At the same time, a wider national quantum communication vision may combine multiple transmission modes.
Assertion (A) – True: India’s recent quantum communication milestone shows that quantum-secure communication can be deployed over existing telecom infrastructure. The successful demonstration of a 1,000-km quantum communication network establishes that Quantum Key Distribution can work over conventional optical fiber networks rather than requiring a completely new dedicated communication backbone. This is significant because practical adoption depends not only on security, but also on whether the technology can be integrated into already available telecom systems at scale.
Reason (R) – True: The demonstrated network used existing telecom fiber cables, which makes the system cost-effective and scalable for wider national deployment. The broader architecture also does not remain confined to fiber alone: it includes free-space and satellite-based communication pathways for long-distance expansion. This multi-modal design is important because fiber is suitable for secure terrestrial links, while free-space and satellite channels help extend quantum-secure communication across wider and strategically important geographies.
Why R explains A: The reason directly explains the assertion. The assertion is about deployability on existing infrastructure, and the reason provides the operational basis for that claim: the network was actually demonstrated on existing fiber cables. This proves that quantum-secure communication is not merely a laboratory concept. It has already moved into an implementation stage compatible with real-world telecom systems. The inclusion of free-space and satellite-based pathways further strengthens the claim by showing that the mission is designed for practical expansion beyond fiber-based terrestrial networks.
1. Hydrofluorocarbons were introduced as substitutes for ozone-depleting substances.
2. Hydrofluorocarbons are being phased down under the Montreal Protocol because they directly deplete stratospheric ozone.
3. India’s HFC phase-down schedule begins from 2032.
Which of the statements given above are correct?
Core Concept: This question tests the distinction between ozone depletion and global warming. HFCs were introduced as alternatives to ozone-depleting substances because they are ozone-friendly, but they later emerged as a climate concern due to their high Global Warming Potential. Their phase-down is therefore climate-driven, not because they deplete ozone.
Statement 1 – Correct: Hydrofluorocarbons were developed and introduced as substitutes for ozone-depleting substances such as Chlorofluorocarbons and Hydrochlorofluorocarbons. The reason was that CFCs and HCFCs contain ozone-depleting elements, especially chlorine, whereas HFCs do not contain chlorine and therefore have zero Ozone Depletion Potential. In that sense, HFCs were considered ozone-friendly alternatives in the transition away from earlier refrigerants and industrial chemicals.
Statement 2 – Incorrect: HFCs are not being phased down because they directly deplete stratospheric ozone. This is the key conceptual trap in the question. Their environmental problem lies elsewhere: they are powerful greenhouse gases with very high Global Warming Potential, in some cases thousands of times higher than carbon dioxide over a comparable time horizon. Therefore, the HFC phase-down under the Kigali Amendment is a climate mitigation measure, not an ozone-depletion control measure.
Statement 3 – Correct: India’s HFC phase-down schedule begins from 2032. Under the Kigali Amendment framework, countries have differentiated timelines, and India falls in the group with a later start to the phase-down pathway. India’s reduction trajectory is gradual and cumulative, beginning with a 10% reduction in 2032, followed by 20% in 2037, 30% in 2042 and 85% in 2047.
Core Concept: This question tests treaty architecture. The Vienna Convention provides the broader framework for ozone protection, the Montreal Protocol operationalizes phase-out of ozone-depleting substances, and the Kigali Amendment expands that framework to phase down HFCs because of their climate impact.
Option (a) – Incorrect: The Vienna Convention is the broader convention framework and did not itself create the specific binding HFC phase-down schedule. That phase-down is linked to the Kigali Amendment under the Montreal Protocol framework.
Option (b) – Correct: The Montreal Protocol was designed to phase out ozone-depleting substances such as CFCs, HCFCs and halons. The Kigali Amendment later brought HFC phase-down into the same treaty architecture because of their high warming impact.
Option (c) – Incorrect: This is a conceptual trap. HFCs were introduced as non-ozone-depleting substitutes and are not targeted because they contain chlorine or bromine that destroy ozone.
Option (d) – Incorrect: The concern here is stratospheric ozone, which protects Earth from harmful ultraviolet radiation. Tropospheric ozone near the Earth’s surface is a different environmental issue.