Underwater Cables

Syllabus: Science and Technology

Source: TH

Context: Airtel’s 2Africa Pearls subsea cable has landed in India, boosting internet capacity by 100 Tbps, highlighting the growing need for robust undersea cable infrastructure.

What Are Underwater Cables?

• Definition: Undersea or submarine cables are fibre-optic cables laid on the ocean floor that enable global internet and telecommunication connectivity.

• Coverage: As of early 2025, there are over 600 active and planned cables globally, spanning 1.48 million kilometres.

How Do They Work?

• Fiber-Optic Technology: Cables carry data using light signals transmitted through hair-thin glass fibres, encoded by lasers at high speeds.

• Signal Reception: Receptors on the other end decode the light signals into usable internet data.

• Seabed Placement: Cables are either buried near shores or laid directly on the ocean floor in deeper regions.

• Routing Strategy: Careful mapping avoids fault lines, anchor zones, and fishing areas to minimize damage risk.

• Transmission Capacity: Each cable can carry hundreds of terabits per second, enabling seamless global data flow.

Key Features of Submarine Cables:

• Thickness: Comparable to a garden hose; core fibres are as thin as a human hair.

• Protection Layers: Composed of plastic, steel wiring, and insulation; extra armouring is used near coastlines.

• Examples:

• Shortest: CeltixConnect (131 km between Ireland and the UK).

• Longest: Asia-America Gateway (20,000 km).

• Landing Points: Connect to onshore landing stations, which then distribute the data via terrestrial networks.

• Global Coverage: Nearly all coastal nations are connected, with redundancy through multiple cables to avoid data blackouts.

Significance of Underwater Cable Connectivity:

• Backbone of Internet: Enables global data transfer including emails, streaming, financial transactions, and more.

• Economic Enabler: Supports $10 trillion in global financial flows and 80% of trade via internet infrastructure.

• Digital Sovereignty: Reduces reliance on satellite-based or foreign-controlled connectivity options.

• National Security: Secure data transfer critical for defense and governance (e.g., encrypted diplomatic comms).

• Growth Driver: Fuels digital economy and innovation (e.g., cloud services, OTT platforms, remote work).

Challenges Associated with Subsea Cables in India

• Vulnerability to Disruptions: Cuts in Red Sea cables affected 25% of India’s internet in 2023.

• Limited Landing Points: 95% of subsea cables land in a 6 km zone in Mumbai, creating a chokepoint.

• Complex Regulations: Over 51 permissions needed to land cables, delaying deployment.

• Lack of Repair Infrastructure: India lacks domestic repair vessels, relying on foreign ships with clearance delays.

• Man-made Damages: Fishing trawlers and dredging often damage cable lines (e.g., Versova coast, Mumbai).

Way Ahead

• Regulatory Reforms: Streamline multi-agency permissions through single-window clearances.

• Geographical Diversification: Develop new landing points (e.g., Vishakhapatnam, Kochi) to reduce chokepoint risk.

• Build Repair Capacity: Invest in Indian subsea cable repair ships and depots to reduce response time.

• Public-Private Partnerships: Encourage investments from telecom and digital giants for infrastructure sharing.

• Strategic Planning: Integrate cable infrastructure into India’s Digital Public Infrastructure roadmap for resilience

Conclusion:

Undersea cables are vital to India’s digital economy, yet the country’s current infrastructure is highly centralized and underprepared for disruptions. Streamlined regulation and strategic expansion are essential to ensure digital resilience and global competitiveness. A robust undersea ecosystem will power India’s vision of Digital Bharat.

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