How Did ESG Reporting in India Reach This Point?
India’s ESG reporting journey has been defined by progressive regulatory intent. For over a decade, listed companies were expected to report on their business responsibility practices, but the framework remained largely narrative and discretionary. Structured, comparable, and independently verified ESG data was the exception, not the norm.
The inflection point came in 2021, when the Securities and Exchange Board of India (SEBI) replaced the Business Responsibility Report (BRR) with the Business Responsibility and Sustainability Report (BRSR), mandating it for the top 1,000 listed entities from FY2022-23. For the first time, sustainability disclosures had standardised metrics, defined principles, and measurable KPIs.
However, standardisation alone did not resolve the credibility question. Disclosed data, however well structured, remained unverified. Investors, lenders, and regulators increasingly demanded that ESG metrics carry the same evidentiary weight as financial figures. That demand gave rise to BRSR Core and, with it, the requirement for independent assurance on a defined set of key ESG performance indicators under 9 ESG attributes
It is within this context that BRSR Core assurance emerges as the next phase in India’s ESG evolution, a shift from reporting intent to validated performance. For companies now falling within SEBI’s phased assurance thresholds , the question is no longer whether to engage with assurance, but how to build systems that can sustain it. This transition is accelerating demand for credible BRSR assurance services in India.
What Is BRSR Core? Understanding the Framework
BRSR Core is a focused subset of the broader BRSR framework, built around a specific set of decision-relevant ESG metrics that are standardised enough for independent verification. While the full BRSR covers a wide range of qualitative and quantitative disclosures, BRSR Core narrows the scope to high-impact, comparable indicators supported by standardized intensity ratios and other verifiable metrics across environmental, social, and governance dimensions.
Structurally, BRSR Core covers nine ESG attributes identified by SEBI as critical for comparability and assurance . These attributes span environmental, social, and governance dimensions, including:
- Greenhouse gas footprint (Scope 1 and Scope 2)
- Energy footprint
- Water footprint
- Embracing circularity – details related to waste management by the entity
- Enabling Gender Diversity in Business
- Enhancing Employee Wellbeing and Safety
- Enabling Inclusive Development
- Fairness in Engaging with Customers and Suppliers
- Open-ness of business
Together, the KPIs under these attributes form the audit-ready core of India’s ESG reporting architecture. The SEBI circular SEBI/HO/CFD/CFD-SEC-2/P/CIR/2023/122 issued on 12 July 2023 formally established this framework and introduced the phased mandatory assurance schedule.
What Is the Phased Rollout Timeline?
SEBI has implemented BRSR Core assurance requirements progressively, based on market capitalisation. The complete phased schedule is as follows:
- FY2023-24: Top 150 listed entities
- FY2024-25: Top 250 listed entities
- FY2025-26: Top 500 listed entities
- FY2026-27: Top 1,000 listed entities
This phased schedule means that companies entering scope in any given year must be prepared for assurance before the close of their reporting period. For example, companies ranked between 251 and 500 face their first year of mandatory assurance in FY2025-26, requiring scoping of engagements, assessment of internal controls , and readiness evaluation well before the reporting cycle concludes on 31 March .
A critical dimension that is often underestimated: from FY2026-27, the top 250 companies are also required to obtain assurance on value chain ESG disclosures on voluntary basis, covering upstream suppliers and downstream distributors.
Why Does the Move to Assurance Matter?Why Does the Move to Assurance Matter?
The shift from disclosure to assurance is not administrative. It represents a structural change in how ESG data is produced, governed, and evaluated.
Historically, sustainability disclosures relied on internally reported figures with no external validation. This improved transparency but left open questions around accuracy, comparability, and the risk of greenwashing. Boards and investors had no independent basis for trusting the numbers.
BRSR Core assurance directly addresses this by introducing independent verification of ESG metrics. Unlike certification, which delivers a pass-or-fail outcome, assurance provides a professional opinion on the reliability of disclosures, based on evidence-backed evaluation of data, processes, and controls.
ESG data is now actively used in investment decisions, lending assessments, credit ratings, and regulatory risk analysis. As a result, its credibility has become as important as its availability. For companies, this changes the nature of ESG reporting entirely. It is no longer sufficient to disclose data. Organisations must now ensure that data is traceable, consistent, and verifiable.
What Changes in Practice for Companies?
The introduction of BRSR Core assurance materially changes how ESG data is prepared, governed, and reviewed within organisations.
Central to this transition is SEBI’s requirement that companies obtain assurance of their BRSR Core disclosures. Reasonable assurance remains the defined benchmark and represents a notably high standard. Unlike limited assurance, which relies on analytical review and plausibility checks, reasonable assurance involves detailed testing of underlying data, validation of calculation methodologies, assessment of internal control systems, and sampling across business units and sites.
This brings ESG reporting closer in rigour to financial audits. Companies must maintain clear evidence trails for all BRSR Core KPIs, supported by documentation, defined methodologies, and controlled processes. Data that was previously collated at year-end must now be tracked and validated continuously throughout the reporting cycle.
In parallel, ESG reporting is becoming more integrated with financial reporting systems, requiring closer coordination between sustainability, finance, and compliance functions. For many organisations, this represents a transition from fragmented, spreadsheet-driven practices to a more governed and traceable data environment. This shift is accelerating engagement with structured BRSR assurance services in India to support readiness, gap assessment, and validation.
How Does a BRSR Core Assurance Engagement Work?
From a consulting and implementation standpoint, BRSR assurance follows a structured methodology grounded in established standards.
The engagement begins with defining the scope, including reporting boundaries, and the assurance level to be applied. A detailed planning phase follows, in which assurers assess risks associated with data accuracy, internal controls, and reporting processes.
The core of the engagement is data verification and testing. This involves validating disclosed figures against source records, reviewing calculation methodologies and underlying assumptions, and performing sampling across business units or plant locations. Assurers also evaluate the effectiveness of internal controls, including standard operating procedures, approval workflows, and data validation mechanisms.
Gaps and inconsistencies are documented, management responses are assessed, and the engagement concludes with the issuance of an assurance statement, which reflects the assurer’s independent opinion on the reliability of the BRSR Core disclosures.
The key insight this process surfaces: assurance does not simply verify numbers. It evaluates the systems and processes that generate those numbers. A disclosure that appears complete but lacks supporting evidence may not withstand scrutiny. Conversely, a disclosure that acknowledges limitations but is supported by clear methodologies and documented controls is often more defensible.
Who Drives Assurance Readiness Internally?
BRSR Core assurance is an organisation-wide responsibility, not a standalone ESG activity. Multiple functions must coordinate to produce and sustain audit-ready disclosures.
- Board and senior management: oversight, accountability, and tone at the top
- ESG and sustainability function: process coordination and KPI ownership
- HR, operations, procurement, and finance: data generation and underlying records
- Plant and unit teams: source-level documentation and evidence maintenance
- Internal audit: reliability checks, control testing, and assurance readiness
- Technology teams: data traceability, system integration, and automated validation
- Company Secretary: regulatory alignment with SEBI requirements and statutory filings
This multi-layered involvement underscores the need for clearly defined ownership, documented processes, and coordinated governance. Where these elements are absent, even complete-looking data will struggle under assurance.
Which Standards and Frameworks Govern BRSR Core Assurance?
BRSR Core assurance draws on a combination of globally recognised standards, which provide structure and consistency to engagement methodologies.
- ISAE 3000 (revised): The primary international standard for non-financial assurance, widely used in audit-led BRSR engagements
- AA1000AS: Adds a stakeholder-centric dimension, focusing on materiality, completeness, and responsiveness
- ISSA 5000: An emerging global standard expected to progressively harmonise sustainability assurance practices
- ISAE 3410: Assurance engagements on GHG statements
- Indian Standards: SSAE 3000 (Assurance on sustainability information) and SAE 3410 (Assurance on GHG statements)
In practice, assurance engagements often draw on multiple standards simultaneously to balance technical rigour with stakeholder relevance. The choice of standards is typically agreed between the organisation and the assurance provider during the scoping phase.
What Are the Operational Challenges for Companies Under BRSR Core Assurance?
As the BRSR Core assurance requirement expands across companies in SEBI’s phased rollout, the operational implications are significant and varied.
Many companies continue to rely on manual processes and spreadsheets for ESG data collection, which creates challenges under reasonable assurance. Data gaps, inconsistent methodologies across sites, and weak evidence trails are among the most common issues surfaced during assurance engagements. As a result, there is a growing demand for technology-enabled ESG reporting platforms that provide data traceability, automated validation, and audit-ready documentation.
Complex measurement areas, including Scope 1 and Scope 2 emissions calculations, water intensity metrics, and social indicators such as workforce diversity ratios and wage data, add further challenges. These often require coordination with third-party data sources, HR systems, and operational databases, increasing the need for structured data governance.
For companies entering the assurance requirement for the first time, the most common mistakes include treating assurance as a year-end exercise, underestimating the evidence burden for the BRSR Core KPIs, and failing to assign clear ownership across functions. Engaging experienced BRSR assurance services in India early in the reporting cycle significantly reduces these risks.
A Practical Approach to BRSR Core Assurance Readiness
Given the scale of internal change required, organisations are increasingly adopting a structured readiness approach rather than treating assurance as a one-time compliance exercise.
The starting point is an honest assessment of current reporting maturity, benchmarked against the BRSR Core KPIs. This identifies which data points are already traceable, which lack documentation, and where calculation methodologies need to be formalised.
From there, the focus shifts to strengthening governance frameworks, defining ownership across functions, and establishing standardised data collection processes. Technology implementation plays a central role at this stage, whether through dedicated ESG platforms or integration with existing ERP and HR systems.
Many organisations conduct mock assurance assessments before formal engagement, which surface evidence gaps and control weaknesses while there is still time to address them. Critically, this readiness work should be treated as an ongoing capability, not a one-time exercise. As assurance requirements expand to include value chain disclosures and new KPIs, the organisations with strong foundational systems will adapt most effectively.
Pierag’s ESG and Sustainability practice supports organisations across this full readiness journey, from gap assessment and governance design through to assurance preparation, execution of BRSR Core assurance engagements, and ongoing ESG reporting.
What Does the Road Ahead Look Like?
BRSR Core assurance is expected to expand in both scope and depth. A key development is the requirement for value chain disclosures by the top 250 companies, which commenced on a voluntary basis from FY 2025-26, with assurance of these disclosures applicable from FY 2026-27 on voluntary basis. This requires organisations to collect and verify ESG data from upstream suppliers and downstream distributors, a step that demands early engagement with value chain partners and robust third-party data protocols.
Regulatory scrutiny is also expected to intensify, particularly around data integrity, consistency across reporting periods, and the quality of internal controls supporting BRSR Core KPI calculations.
Globally, the convergence of sustainability assurance standards, particularly the emergence of ISSA 5000, is likely to progressively align Indian assurance practices with international frameworks, increasing comparability and investor confidence in BRSR Core disclosures.
Conclusion
BRSR Core assurance marks a decisive shift in India’s ESG landscape, moving from disclosure-driven reporting to system-driven validation. For companies now falling within SEBI’s phased assurance thresholds, this transition calls for more than compliance. It requires a fundamental rethinking of how ESG data is generated, governed, and verified across the organisation.
The KPIs across nine ESG attributes that form BRSR Core are not simply a reporting checklist. They are the foundation of a credible, audit-ready sustainability practice. Organisations that invest now in building robust controls, clear ownership structures, and traceable data systems will not only meet the current assurance requirement, but will be better positioned as the scope expands to value chain disclosures and the top 1,000 listed entities.
As BRSR assurance services in India continue to evolve, the focus is converging on a straightforward but critical outcome: sustainability reporting that is not only comprehensive, but credible, consistent, and defensible.
Frequently Asked Questions
What is BRSR Core assurance?
BRSR Core assurance is the independent verification of a company’s key ESG performance indicators under India’s BRSR framework. It involves a professional assurance provider reviewing the data, processes, and controls behind specific KPIs across nine ESG attributes and issuing an opinion on their reliability. SEBI has mandated assurance, the highest standard, for India’s top listed companies on a phased schedule.
What is the difference between BRSR and BRSR Core?
BRSR is the full Business Responsibility and Sustainability Report, which covers a wide range of qualitative and quantitative ESG disclosures across nine NGRBC principles. BRSR Core is a curated subset of BRSR, focused on high-impact KPIs that are standardised and measurable enough for independent assurance. BRSR Core carries stricter requirements, including mandatory assurance for the top 1,000 listed entities in a phased manner.
What is the difference between limited assurance and reasonable assurance?
Limited assurance involves analytical review and plausibility checks, resulting in a conclusion that nothing came to the assurer’s attention that would suggest the disclosures are materially misstated. Reasonable assurance, involves a higher level of evidence gathering, including detailed data testing, sampling across sites, and internal controls assessment. It results in a positive opinion on the reliability of the disclosures.
Which companies need BRSR Core assurance in FY2026-27?
All listed entities ranked within the top 1000 by market capitalisation are required to obtain reasonable assurance on their BRSR Core disclosures for FY2026-27. This includes:
- Top 150 entities, who have been subject to the requirement since FY2023 24
- Companies ranked 151 to 250, who have been subject to the requirement since FY2024 25
- Companies ranked 251 to 500, who entered scope in FY2025 26
- Companies ranked 501 to 1,000, who are entering the assurance requirement for the first time in FY2026 27
In addition, the top 250 companies are required to provide value chain ESG disclosures on a voluntary basis, with assurance of those disclosures also applicable from FY2026 27.
What are the nine attributes of BRSR Core?
BRSR Core is structured around nine ESG attributes aligned with SEBI’s nine NGRBC principles. These cover: Open-ness of business; fairness in engaging with customers and suppliers; enabling inclusive development; enabling gender diversity in business ; enhancing employee wellbeing and safety; Embracing circularity – details related to waste management by the entity; water footprint; energy footprint; and GHG footprint.
