If your company files BRSR, you already know the reporting requirements. But BRSR Core adds a layer that changes everything: third-party assurance.
It's not enough to report your ESG data anymore. An independent auditor now needs to verify it. And from FY 2025-26, this extends beyond the top 150 companies to their entire value chain.
What Is BRSR Core?
BRSR Core is a focused subset of the broader BRSR framework. While BRSR covers comprehensive ESG disclosures across 9 NGRBC principles, BRSR Core narrows the focus to 9 specific, quantitative KPIs that must undergo reasonable assurance from an independent auditor.
Think of it this way: BRSR is the full report. BRSR Core is the subset that gets audited.
BRSR Core transforms ESG reporting from a self-declaration exercise into an independently verified disclosure - similar to how financial statements require a statutory audit.
Who Needs BRSR Core Assurance?
| Category | Requirement | Timeline |
|---|---|---|
| Top 150 listed companies (by market cap) | BRSR Core with reasonable assurance | Mandatory from FY 2023-24 |
| Top 250 listed companies | BRSR Core with reasonable assurance | Phased implementation |
| Value chain partners of top 250 | Provide BRSR Core data to listed clients | From FY 2025-26 |
| Top 1,000 listed companies | Full BRSR filing (assurance not yet mandatory) | Ongoing |
The value chain extension is the game-changer. If you're an unlisted supplier, manufacturer, or service provider to a top 250 listed company, your client will ask you for BRSR Core data. Not having it could cost you the contract.
The 9 BRSR Core KPIs
These are the specific indicators that require assurance. Each is quantitative, measurable, and auditable:
Environmental KPIs
- GHG emissions intensity - Scope 1 and Scope 2 emissions per rupee of turnover, measured in tCO2e using the GHG Protocol
- Water consumption intensity - Total water consumed per rupee of turnover (kilolitres/INR)
- Waste diverted from disposal - Percentage of total waste recycled, reused, or recovered
- Energy consumption intensity - Total energy consumed per rupee of turnover (GJ/INR)
Social KPIs
- Gender diversity - Percentage of women in total workforce and on the board
- Gross wages paid to women vs men - Median remuneration ratio (female to male)
- Occupational health & safety training - Percentage of employees and workers who received OHS training
Governance KPIs
- Inputs sourced sustainably - Percentage of inputs (by value) sourced from verified sustainable sources
- Fair engagement with value chain partners - Policies and practices for equitable dealing with suppliers
All 9 KPIs must be reported with intensity metrics (per rupee of turnover) where applicable. This makes them comparable across companies of different sizes - a deliberate design choice by SEBI to enable benchmarking.
Limited vs Reasonable Assurance - What's the Difference?
This distinction matters because BRSR Core specifically requires reasonable assurance, which is the higher standard:
| Aspect | Limited Assurance | Reasonable Assurance |
|---|---|---|
| Conclusion | "Nothing has come to our attention..." | "In our opinion, the data is fairly stated..." |
| Evidence | Inquiry and analytical procedures | Detailed testing, sampling, site visits |
| Depth | Less rigorous | Same rigor as financial audit |
| Cost | Lower | Higher (typically 1.5-2x limited) |
| Standard | ISAE 3000 / ISAE 3410 | ISAE 3000 / ISAE 3410 |
| BRSR Core requirement | Not sufficient | Required |
Reasonable assurance means the auditor actively tests your data - visiting facilities, checking meters, sampling records, verifying calculations. It's not a desk review.
Who Can Provide BRSR Core Assurance?
SEBI allows assurance from:
- Statutory auditors (CA firms) with ESG assurance capability
- External assurance providers accredited by recognized bodies
- Sustainability assurance specialists with relevant credentials (e.g., ISO 14064 Lead Verifier, ISAE 3000 practitioners)
The assurance provider must be independent of the company and cannot have provided consulting services on the same BRSR data they're assuring.
This independence requirement is crucial. Your ESG consultant can help you prepare the data, but a different firm must assure it. Plan for both.
How BRSR Core Affects Your Value Chain
From FY 2025-26, SEBI requires the top 250 listed companies to obtain BRSR Core data from their value chain partners. This has a cascading effect:
- Listed companies will send data requests to their suppliers, asking for the 9 KPIs
- Unlisted suppliers need systems to collect and report emissions, water, waste, energy, and social data
- MSMEs in the value chain face the biggest challenge - they typically don't have ESG data collection systems in place
- Procurement teams will increasingly use BRSR Core readiness as a vendor selection criterion
This mirrors what's happening globally. The EU's CSRD similarly requires value chain data from suppliers. Indian companies in both domestic and export supply chains now face dual pressure.
How to Prepare for BRSR Core Assurance
Step 1: Gap assessment. Map your current data collection against the 9 BRSR Core KPIs. Identify what you already track, what's partially available, and what's completely missing.
Step 2: Set up data systems. Establish metering, measurement, and recording systems for each KPI. GHG emissions need fuel logs and electricity bills. Water needs flow meters. Waste needs weighbridge records. This is the most time-consuming step.
Step 3: Calculate intensity metrics. All environmental KPIs need to be expressed per rupee of turnover. Ensure you have the methodology documented - auditors will verify your calculation approach.
Step 4: Document everything. Assurance providers need an evidence trail. Maintain source documents, calculation sheets, methodology notes, and assumption registers. If it's not documented, it doesn't exist for the auditor.
Step 5: Do a dry run. Before the formal assurance engagement, conduct an internal review mimicking an audit. Test your data against the 9 KPIs. Fix gaps before the auditor finds them.
Step 6: Engage your assurance provider early. Don't wait until the report is ready. Engage the auditor at the start of the data collection cycle so they can advise on methodology and flag issues early.
Common Mistakes Companies Make
- "We'll use estimated data" - Reasonable assurance requires actual measured data, not estimates. Auditors will flag estimations without supporting methodology.
- "Our financial auditor can do it" - Your CA firm may not have ESG assurance capability. Verify they have ISAE 3000 experience and environmental/social audit expertise.
- "We'll start next quarter" - Data collection for a full financial year needs to start at the beginning of the year. Retroactive data gathering is error-prone and hard to assure.
- "Only the top 150 need to worry" - If you're in the supply chain of a top 250 company, you'll need to provide BRSR Core data even if you're not listed.
- "ESG data doesn't need the same rigor as financial data" - SEBI explicitly chose reasonable assurance (the financial audit standard) for a reason. Treat ESG data with the same discipline as financial data.
BRSR Core vs Full BRSR - Quick Comparison
| Aspect | Full BRSR | BRSR Core |
|---|---|---|
| Scope | All 9 NGRBC principles, 130+ disclosures | 9 specific quantitative KPIs |
| Applicability | Top 1,000 listed companies | Top 150 (expanding to 250) |
| Assurance | Not required | Reasonable assurance mandatory |
| Value chain | Limited disclosure | Data required from value chain partners |
| Nature | Qualitative + quantitative | Purely quantitative, intensity-based |
| Comparability | Moderate | High (intensity metrics enable benchmarking) |
What This Means for Different Industries
- Chemicals & Petrochemicals - GHG intensity and waste diversion are the toughest KPIs. Process emissions are hard to reduce and hazardous waste disposal methods need careful documentation.
- Manufacturing - Energy intensity is the focus. Factory-level metering and sub-metering become essential for accurate reporting.
- IT & Services - Scope 2 (electricity) dominates. Gender diversity and pay equity metrics are where IT companies face the most scrutiny.
- Textiles - Water consumption intensity is critical. Dyeing and finishing operations are water-intensive and need detailed tracking.
- Pharmaceuticals - Hazardous waste management and OHS training coverage are key areas for pharma companies.
Use our free Carbon Footprint Calculator to get a quick estimate of your GHG emissions baseline, or download our BRSR Readiness Checklist for a complete preparation guide.
Frequently Asked Questions
BRSR Core is a subset of SEBI's BRSR framework focusing on 9 key ESG KPIs that require reasonable assurance (third-party verification). It applies to the top 150 listed companies and extends to value chain partners of the top 250 from FY 2025-26.
Top 150 listed companies must get reasonable assurance. Value chain partners of top 250 must provide BRSR Core data. The scope is expanding progressively.
GHG emissions intensity, water consumption intensity, waste diverted from disposal, energy consumption intensity, gender diversity, gross wages (women vs men), OHS training coverage, sustainable sourcing, and fair value chain engagement.
Limited assurance is a desk review ("nothing has come to our attention"). Reasonable assurance is rigorous testing with site visits and evidence gathering ("in our opinion, fairly stated"). BRSR Core requires reasonable assurance - the higher standard.
Related reading: What is BRSR Reporting? | Scope 1, 2, 3 Explained | EU CSRD for Indian Exporters | ESG vs CSR | How to Choose an ESG Consultant
Need help with BRSR Core assurance readiness?
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