Foundations · ESG and Sustainable Finance

    Green Bonds and Sustainability-Linked Debt

    7 min readLast reviewed: July 2025

    Intuition

    A green bond is a standard fixed-income instrument with one important addition: the proceeds are contractually restricted to use for defined environmental or climate-related purposes, renewable energy projects, energy efficiency, clean transportation, sustainable water management, and similar categories.

    Green bonds were first issued by the World Bank and European Investment Bank in 2007–08. India's green bond market has grown significantly, with issuers ranging from REC Ltd and IREDA to Adani Green Energy and the Government of India (which issued its first sovereign green bond in 2023).

    From an analytical perspective, the critical question is whether the "green" label adds financial value. In principle, a "greenium" (a lower yield premium paid by investors who want ESG-aligned assets) should exist if green bonds are oversubscribed. In practice, the greenium is often small and inconsistent.

    Mechanics

    Types of sustainable debt instruments:

    Green Bonds: Proceeds earmarked for environmental projects. Governed by ICMA Green Bond Principles (GBP).

    Social Bonds: Proceeds for social outcomes (affordable housing, healthcare, education). ICMA Social Bond Principles.

    Sustainability Bonds: Proceeds for a mix of green and social projects.

    Sustainability-Linked Bonds (SLBs): A newer category, proceeds can be used for any purpose, but the coupon increases if the issuer misses pre-agreed sustainability KPIs (e.g., "if Scope 1 emissions don't fall 25% by 2027, coupon steps up by 25 bps"). KPI selection and ambitiousness are key.

    SEBI Green Bond Framework (2023):

    • Updated to align with ICMA GBP
    • Defines eligible categories: renewable energy, clean transportation, sustainable water, energy efficiency, sustainable management of living natural resources, climate change adaptation, pollution prevention, green buildings
    • Requires second-party opinion and post-issuance reporting

    Process:

    1. Issuer sets green bond framework (eligible projects, use of proceeds, management of proceeds, reporting)
    2. Second-party opinion (SPO) from an independent verifier (CICERO, Sustainalytics, CRISIL)
    3. Bond issuance
    4. Annual reporting on allocation and impact

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