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India has entered its first full BRSR Core assurance cycle covering all top 1,000 listed companies. The disclosures won’t be filed until mid-2027, but the evidence an auditor will test must exist now. Here is why Q3 FY2026-27 is the decisive quarter, and what to do in the next twelve weeks.
The Baseline Has Shifted
For most of its early years, ESG reporting in India was a disclosure exercise. Companies gathered what they had, filled in the format, and filed. That era has now closed.
With the onset of FY 2026-27, BRSR Core assurance has become mandatory for all top 1,000 listed companies by market capitalisation, completing a phased rollout that began with India’s top 150 companies in FY 2023-24. By FY 2026-27, reasonable assurance on BRSR Core is mandatory for all top 1,000 listed companies by market capitalisation, placing India among the most rigorous ESG assurance regimes in the world.
The BRSR Core assurance glide path
| Financial Year | Companies Covered |
| FY 2023-24 | Top 150 |
| FY 2024-25 | Top 250 |
| FY 2025-26 | Top 500 |
| FY 2026-27 | All top 1,000 |
Source: SEBI phased rollout, via Benchmark Gensuite
For the roughly 500 companies newly covered this year (those ranked 501 to 1,000 by market capitalization) this is not a disclosure exercise. It is an audit. And they have roughly 12 months to set up the data systems that the assurance provider will test.
What “Reasonable Assurance” Actually Demands
Reasonable assurance requires auditors to trace every disclosed metric back to source documents, verify that calculation methods are consistent and documented, and assess whether internal controls are strong enough to produce reliable data year after year. BRSR Core covers nine specific ESG attributes:
| # | BRSR Core Attribute |
| 1 | Greenhouse Gas Emissions |
| 2 | Water Management |
| 3 | Energy Consumption |
| 4 | Waste Management |
| 5 | Gender Diversity |
| 6 | Inclusive Development |
| 7 | Customer Conduct |
| 8 | Wages Distribution |
| 9 | Business Openness |
For each attribute, auditors will look beyond the numbers to verify data origin, data ownership, calculation methodology, and error prevention.
The quality of a company’s ESG data is now a function of how that data is governed. A company can have strong sustainability performance and still produce an assurance report that falls short if its data infrastructure is fragmented or inconsistently managed.
The Nine Evidence Gaps Most Companies Haven’t Closed
The gap between what companies have and what auditors demand shows up in nine specific places. Here are the most consequential, drawn from the practical evidence requirements that assurance providers are testing:
| Gap | What Finance Teams Have | What Auditors Demand |
| GHG emissions intensity | Annual electricity bill × emission factor | Sub-meter readings, documented CEA grid factor version, IPCC AR version for fuels, calibration certificates |
| Water withdrawal | Municipal water bill amounts | Withdrawal sub-metering from all sources (municipal, borewell, tanker, surface water, recycled), tanker logbooks |
| Boundary consistency | Different boundaries for different attributes | Same reporting boundary across all nine attributes |
| Emission factor version | Using current year’s factor | Documented version, the CEA grid factor changes annually as the energy mix shifts |
| Calibration certificates | Never asked before | Valid calibration certificates for emission monitoring instruments |
| Scope 2 methodology | Location-based or market-based, inconsistently applied | Consistent, documented methodology across every site |
Most companies fail on the emission factor version, using the wrong year’s CEA grid factor. And on sub-metering, relying on aggregate bills rather than meter readings, which fail when the bill includes consumption of an unrelated activity.
The water withdrawal error catches finance teams in two ways. First, confusing “consumption” (a smaller number) with “withdrawal” (a larger number including recycled). Second, ignoring tankers, a factory with municipal supply plus emergency tanker deliveries often forgets to include the tanker quantity. The assurance provider will ask for the daily tanker logbook.
The Cost of Getting It Wrong
The regulatory framework itself anticipated this. SEBI’s BRSR Core circular requires assurance providers to obtain sufficient and appropriate evidence, and to express a conclusion on whether the disclosures are fairly presented in all material respects. Where that evidence is not available, the framework provides for modification of the opinion.
The first full assurance cycle under this framework has now been completed, and the filings are public. Across the FY 2024-25 BRSR disclosures from the top 150 companies, at least one listed entity received a qualified assurance opinion, with the assurance provider unable to obtain sufficient appropriate evidence for certain BRSR Core disclosures. The qualification cited gaps in data and evidence availability, internal controls, and lack of uniformity in implementation of controls and reporting processes.