Which suppliers should I ask for emissions data first?
Start with the few suppliers behind most of your estimated Scope 3 emissions, not most of your spend. Rank purchases by spend or quantity times a rough factor, take the suppliers that make up about 80% of the total, then move up anyone selling CBAM goods or whom your buyer names.
Step 1: screen every supplier roughly
- Export a year of purchases by supplier, with spend, quantity, unit and HSN code.
- Assign each supplier a rough factor for what they sell: a spend-based factor per rupee, or a material factor per tonne where you know the quantity.
- Multiply and rank. The point is the order, not the exact tonnes; screening factors can be off by a wide margin and are fine for this job.
Step 2: apply the GHG Protocol screening criteria
The Scope 3 Standard (chapter 6) suggests weighing more than size. After ranking by estimated emissions, move a supplier up the list if:
- You have influence: a large share of their sales, a long contract, or a renewal coming up.
- They create risk: CBAM-covered goods such as steel, aluminium or fertilisers, where actual data cuts your EU buyer's cost.
- A stakeholder asks: your customer, lender or an SBTi target names that category.
- You outsourced a process you used to run, such as heat treatment or plating, because those emissions used to sit in your own Scope 1 and 2.
Who can wait
- Large spend with low emissions: software, professional services, rent. Spend-based estimates are good enough.
- Traders who resell without processing, unless you can reach the manufacturer behind them.
- One-off purchases you will not repeat next year.
A decision rule for the first round
Ask the top five to ten suppliers by estimated emissions, plus any CBAM-goods supplier, for activity data or a product footprint. Use averages for everyone else this year, and redo the ranking each year as supplier data replaces estimates.
Illustration: ranking six supplier groups
- Steel coil: ₹200 lakh x 4.0 t CO2e per lakh = 800 t
- Aluminium extrusions: ₹50 lakh x 5.0 = 250 t
- Plastic granules: ₹60 lakh x 1.5 = 90 t
- Machining job work: ₹80 lakh x 0.5 = 40 t
- Corrugated boxes: ₹40 lakh x 0.8 = 32 t
- 40 other suppliers: ₹170 lakh x 0.3 = 51 t
- Total: ₹600 lakh and 1,263 t; steel and aluminium are 1,050 t, about 83% of emissions on 42% of spend
Factors here are illustrations chosen to show the method, not published values. Among single suppliers, job work is second by spend but fourth by emissions.
What Senseible does here
Senseible reads purchase invoices and keeps spend, quantity and HSN code by supplier in a separate supplier evidence trail, which gives you the list to rank. It does not apply spend-based factors; use the supplier emissions risk calculator or your own factors for the screen.
Sources: GHG Protocol Corporate Value Chain (Scope 3) Standard (2011), chapter 6, GHG Protocol Technical Guidance for Calculating Scope 3 Emissions (2013)
Last reviewed 2026-10-15.