Overview

Previous Year UPSC-CSE Questions By the end you will be able to draft model answers for the following UPSC questions. Each question carries a collapsible framework showing how to approach it in the exam.

  1. UPSC Mains 2022 GS-IIIWhat are the different elements of cyber security? Keeping in view the challenges in cyber security, examine the extent to which India has successfully developed a comprehensive National Cyber Security Strategy.
    How to structure the answer in the exam

    Directive verb: Examine · Approach: Set out the elements of cyber security, then assess how far India's strategy and capabilities meet the challenges.

    Introduction: Open by defining cyber security and naming its core elements.

    Body (sub-themes to develop):

    • Elements: network, application, data, and communication security.
    • Challenges: cross-border attacks, data theft, and evolving threats.
    • Capability: quantum-secure communication under the National Quantum Mission.
    • Gaps: coordination, skilled workforce, and a comprehensive strategy.
    • The 1,000-km quantum link as a step in strengthening secure communication.

    Conclusion: Conclude that India is building strong capabilities but needs a comprehensive, well-coordinated cyber-security strategy.

The National Quantum Mission (NQM) is India's flagship programme to build quantum technologies, approved by the Union Cabinet on 19 April 2023 with an outlay of Rs 6,003.65 crore for 2023-24 to 2030-31. On 8 April 2026, the mission demonstrated a 1,000-km quantum-secure communication link using quantum key distribution, one of the longest such deployments in the world. The achievement, built on indigenous technology, marks rapid progress towards the mission's eight-year target of 2,000 km.

Why the quantum milestone is in focus

A 1,000-km quantum-secure link is demonstrated

On 8 April 2026, the National Quantum Mission announced a 1,000-km quantum-secure communication link, demonstrated with indigenous technology. It is among the longest such deployments anywhere in the world.

Quantum key distribution shares an encryption key encoded on single particles of light, so any attempt to intercept it disturbs the key and is detected. The National Quantum Mission is India's eight-year programme to build such quantum technologies.

The achievement matters because it arrives within three years of the mission's launch, well ahead of the timeline set for the 2,000 km target. The Secretary of the Department of Science and Technology called it a landmark advance in secure quantum communication.

The key elements of the development are:

  • Milestone: a 1,000-km quantum-secure communication link, announced on 8 April 2026.
  • Method: quantum key distribution, which exposes any eavesdropping.
  • Mission: the National Quantum Mission, with a Rs 6,003.65 crore outlay.
  • Target: secure links over 2,000 km within the eight-year mission.

Why the milestone matters

Secure communication and a sovereign capability

A quantum-secured link cannot be tapped without leaving a trace, so the 1,000-km demonstration directly strengthens the security of sensitive communication for defence, financial systems and critical infrastructure.

The link rests on indigenous technology from a startup supported under the mission, reducing dependence on foreign systems for the most sensitive layer of communication.

It also signals pace. Reaching 1,000 km within three years, half of the 2,000 km target, shows the mission is moving faster than its envisaged timeline.

Progress towards the targetQuantum-secure communication rangeAchieved by April 20261,000 kmquantum-secure linkEight-year target2,000 kminter-city and satellite-basedHalf the target reached within three years of launch.Figure 1. From a 1,000-km link towards 2,000 km.Department of Science and Technology; PIB.Digitally LearnCopyright (c) 2026. All Rights Reserved.

What the milestone signifies

Security, self-reliance and a head start in a strategic race

Three threads carry the weight: communication security, indigenous capability, and a head start in a strategic global race.

First, communication security. Quantum-secured links protect the most sensitive traffic, in defence and finance, against interception that ordinary encryption may one day fail to stop.

Second, indigenous capability. The link uses home-grown technology developed under the mission, placing the core of secure communication in Indian hands rather than imported systems.

Third, the strategic race. Quantum technology is a contested frontier among major powers, and an early lead in secure communication gives India both leverage and resilience.

Distinguishing features of the mission

The mission at a glance

The table sets out the key facts, so the shape and scale of the National Quantum Mission are visible at a glance.

Feature Detail
Mission National Quantum Mission (NQM)
Outlay Rs 6,003.65 crore (2023-24 to 2030-31)
Approved Union Cabinet, 19 April 2023
Latest milestone 1,000-km quantum-secure link, 8 April 2026
Communication target Secure links over 2,000 km

Three features that define the mission

Three traits set the National Quantum Mission apart from a single research grant:

  1. (i) Four thematic verticals. It works across quantum computing, communication, sensing and metrology, and materials and devices.
  2. (ii) Four thematic hubs. Dedicated hubs sit at IISc Bengaluru and the IITs at Madras, Bombay and Delhi, each leading one vertical.
  3. (iii) Concrete targets. It aims for quantum computers with 50 to 1,000 physical qubits and secure links over 2,000 km within eight years.
Four verticals, four hubsHow the mission is organisedQuantum Computing50 to 1,000 physical qubits.Hub: IISc Bengaluru.Quantum CommunicationSecure links over 2,000 km.Hub: IIT Madras.Sensing and MetrologyUltra-precise measurement.Hub: IIT Bombay.Materials and DevicesBuilding blocks for hardware.Hub: IIT Delhi.Figure 2. Four verticals led by four thematic hubs.Department of Science and Technology.Digitally LearnCopyright (c) 2026. All Rights Reserved.

Observable outcomes

Three trackable outcomes

The 1,000-km demonstration translates into three developments to watch in the mission.

  1. (a) Longer links. The next step is to extend secure communication towards the 2,000 km target, across cities and via satellite.
  2. (b) Real deployment. The technology is meant to move from demonstration to use in defence, banking and government networks.
  3. (c) Wider ecosystem. The thematic hubs and supported startups are expected to deliver more quantum hardware and applications.

A demonstration over a test link is a beginning. Reliable, round-the-clock operation on live national networks is what will prove the technology at scale.

Cyber security, the post-quantum threat and digital sovereignty

Why quantum-secure links matter for India's digital future

The milestone connects to cyber security, because quantum key distribution offers a defence whose strength rests on the laws of physics rather than on the difficulty of a calculation.

It answers the post-quantum threat, the worry that powerful quantum computers could one day break the encryption that protects banking, defence and government data.

It also advances digital sovereignty, since owning the secure-communication layer at home reduces reliance on foreign technology for the nation's most sensitive traffic.

Securing a link with physicsHow quantum key distribution worksSenderEncodes a key on light.Quantum keySingle light particles.ReceiverShares the same key.Any eavesdropping disturbs the key and is detected.Figure 3. Sender, quantum key, receiver.Department of Science and Technology.Digitally LearnCopyright (c) 2026. All Rights Reserved.

UPSC relevance and exam focus

Where this fits in the UPSC-CSE syllabus

This topic maps to General Studies Paper III: developments in science and technology, indigenisation of technology, and cyber security, with links to internal security.

For Prelims, hold the high-yield facts: the mission's outlay and timeframe, the four verticals, the thematic hubs, and what quantum key distribution does.

For Mains, two framings recur: quantum technology in India's cyber-security architecture, and indigenisation of strategic technologies.

Recurring linked concepts an aspirant should keep in working memory:

  • National Quantum Mission: Rs 6,003.65 crore, 2023-24 to 2030-31, four verticals.
  • Quantum key distribution: secure communication where tapping is detectable.
  • Thematic hubs: IISc Bengaluru and IITs Madras, Bombay and Delhi.
  • Post-quantum threat: the risk that quantum computers break current encryption.

Quantum key distribution secures the sharing of an encryption key; it is not the same as a general-purpose quantum computer. Confusing the two is an error.

Do not treat quantum technology as only a research story. A balanced answer links it to security, the economy and strategic competition.

Prelims MCQ practice

Each question below tests one specific concept on the topic. Click to reveal the answer and a full option-wise explanation.

Q1. Consider the following statements regarding the National Quantum Mission (NQM):

  1. It was approved by the Union Cabinet in 2023.
  2. It has an outlay of Rs 6,003.65 crore.
  3. It runs through four thematic hubs.

Which of the statements given above is/are correct?

  1. 1 and 2 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3
Show answer and explanation

Answer: 1, 2 and 3

Explanation.

All three are correct. The NQM was approved by the Union Cabinet in 2023, has an outlay of Rs 6,003.65 crore, and runs through four thematic hubs. Hence 1, 2 and 3.

Q2. Quantum key distribution (QKD) is best described as a method that:

  1. Builds a general-purpose quantum computer
  2. Shares an encryption key so that any eavesdropping is detectable
  3. Replaces optical fibre with copper wire
  4. Generates electricity from light
Show answer and explanation

Answer: Shares an encryption key so that any eavesdropping is detectable

Explanation.

Option (b) is correct. QKD shares an encryption key encoded on single particles of light, so any interception disturbs the key and is detected. It is not a quantum computer. Hence option (b).

Q3. The 1,000-km milestone of April 2026 relates to which vertical of the National Quantum Mission?

  1. Quantum computing
  2. Quantum communication
  3. Quantum sensing and metrology
  4. Quantum materials and devices
Show answer and explanation

Answer: Quantum communication

Explanation.

Option (b) is correct. The 1,000-km quantum-secure link is an achievement in quantum communication, one of the mission's four verticals. Hence option (b).

Q4. Consider the following statements about the April 2026 quantum milestone:

  1. India demonstrated a 1,000-km quantum-secure communication link.
  2. It used quantum key distribution.
  3. It was built on indigenous technology.

Which of the statements given above is/are correct?

  1. 1 and 2 only
  2. 2 and 3 only
  3. 1 and 3 only
  4. 1, 2 and 3
Show answer and explanation

Answer: 1, 2 and 3

Explanation.

All three are correct. India demonstrated a 1,000-km quantum-secure link using quantum key distribution, built on indigenous technology. Hence 1, 2 and 3.

Q5. Within eight years, the National Quantum Mission aims to build quantum computers with how many physical qubits?

  1. 5 to 10
  2. 50 to 1,000
  3. Exactly one million
  4. No target is set
Show answer and explanation

Answer: 50 to 1,000

Explanation.

Option (b) is correct. The mission targets intermediate-scale quantum computers with 50 to 1,000 physical qubits in eight years, on platforms such as superconducting and photonic technology. Hence option (b).

Q6. Consider the following pairs of National Quantum Mission verticals and their thematic hubs:

  1. Quantum Computing : IISc Bengaluru
  2. Quantum Communication : IIT Madras
  3. Quantum Materials and Devices : IIT Delhi

How many of the pairs given above are correctly matched?

  1. Only one
  2. Only two
  3. All three
  4. None
Show answer and explanation

Answer: All three

Explanation.

All three pairs are correct. Quantum computing is led from IISc Bengaluru, communication from IIT Madras, and materials and devices from IIT Delhi, while sensing and metrology is led from IIT Bombay. Hence all three.

Sources and Further Reading

Editorial Disclaimer

This briefing explains the National Quantum Mission milestone for UPSC preparation. The facts are drawn from the Department of Science and Technology and the Press Information Bureau. It is an explainer, not a substitute for official communications.