CMVR / TREM-IV emission norms for tractors and off-road engines
What TREM Stage IV means for tractor and engine manufacturers today, where the TREM-V trajectory is heading, and the type-approval workstreams behind both.
On this page
Emission norms are where tractor and engine programmes most often slip, because the rules are staged by horsepower band and the next stage is still moving. This guide gives manufacturers the current picture and the trajectory — and flags clearly what is still draft.
For the full type-approval context around this — Rule 126, AIS-017, AIS-037 — read it alongside the ARAI/ICAT vs FMTTI guide and the CMVR & TREM-IV service page.
TREM is not BS-VI
The first thing to get right: TREM Stage IV is the off-highway agricultural emission norm — tractors, power tillers, combine harvesters — and it is separate from BS-VI, the on-road motor-vehicle stage. The two were formally separated by the operative notification GSR 598(E) dated 30 September 2020 (preceded by the draft GSR 491(E) of 5 August 2020). A tractor's emission compliance is not satisfied by an on-road BS-VI engine certificate; the off-road norm has its own test cycles under AIS-137.
This matters for engine and casting bases like Kolhapur and Rajkot, where the same foundry-and-engine ecosystem can supply both on-road and off-road applications and the compliance regimes must not be confused.
What is under TREM-IV today
TREM Stage IV applies by power band:
| Segment | TREM-IV status |
|---|---|
| Above 37 kW (≈50 HP and above) | Under TREM-IV |
| 19–37 kW (25–50 HP) | Not under TREM-IV; continues at the previous stage pending the TREM-V transition |
Emission testing for TREM-IV runs under AIS-137 (the emission test method for agricultural tractors), carried out at ARAI or ICAT. This is a parallel workstream to the AIS-017 type-approval cycle, with AIS-007 covering tractor technical specifications and AIS-037 the Conformity of Production verification that keeps a granted approval valid in series production. Accreditation of the whole arrangement sits under Rule 126 of the CMVR.
The TREM-V trajectory — read this as draft
A TREM Stage V trajectory is in draft. The figures below come from a draft notification and trade-press coverage; they are not final, and a tractor programme should not be committed against them without confirming the gazette.
The shape of the trajectory matters more than the exact dates for planning: the extremes (largest and smallest tractors) move first, and the high-volume mid-segment gets a phased path. If you build in the 25–50 HP band — the volume heart of the Indian market — you have the most runway, but also the most to plan for.
What this means for your programme
Three practical implications for a manufacturer:
- Know your band. Your emission obligations are set by your HP/kW band, not by a single national date. Map every model to its band.
- Run emission testing in parallel. AIS-137 work at ARAI/ICAT does not have to wait for the rest of the type-approval cycle. Sequencing it serially is a common, avoidable delay.
- Protect Conformity of Production. AIS-037 CoP is not a one-time gate — it is ongoing. Build the quality systems that keep series production inside the approved envelope, or risk the approval.
We run the emission and type-approval workstreams together with manufacturers; see CMVR & TREM-IV Compliance and the broader Certification & Homologation practice.
Frequently asked questions
- BS-VI is the on-road motor-vehicle emission stage (cars, trucks, buses). TREM Stage IV is the off-highway agricultural emission norm for tractors, power tillers and combine harvesters, with its own test cycles under AIS-137. The two were formally separated by the operative notification GSR 598(E) dated 30 September 2020, so a tractor's emission compliance is not satisfied by an on-road BS-VI engine certificate.
- Tractors above 37 kW (≈50 HP and above) are under TREM Stage IV. The 19–37 kW (25–50 HP) band is not under TREM-IV and continues at the previous emission stage pending the TREM-V transition. Emission testing runs under AIS-137 at ARAI or ICAT.
- TREM Stage V is in draft, not final. A draft notification reported in February 2026 proposes 1 October 2026 for the above-75 HP and below-25 HP segments, with the 25–50 HP mid-segment moving via TREM IIIAA from 1 April 2028 then full TREM-V from 1 April 2032, and the 50–75 HP segment upgrading directly to TREM-V from 1 April 2032. These dates are draft and the final gazette is pending — confirm before committing a programme.
- AIS-137 emission testing (at ARAI or ICAT) is a workstream within the broader CMVR type-approval. It runs in parallel with the AIS-017 type-approval cycle and AIS-007 specifications, and AIS-037 Conformity of Production keeps the granted approval valid in series production. Running emission testing in parallel rather than in sequence avoids unnecessary delay.
- [1]AIS-137 — Emission test method for agricultural tractors (TREM IV)— Automotive Research Association of India; accessed 2026-06-04
- [2]GSR 598(E), 30 September 2020 — operative notification separating TREM (CEV) from Bharat Stage— Ministry of Road Transport & Highways; accessed 2026-06-04
- [3]Govt drafts TREM-V for tractors from October 2026 (draft coverage)— Autocar Professional (industry trade press; draft notification coverage); accessed 2026-06-04
Devendra K Jha· Director, AgriMachinery Consulting
Engineer-leader and founder of AgriMachinery Consulting. Works with India's small and unorganised farm-machinery manufacturers on certification, homologation, subsidy empanelment, supply chain and dealer-network strategy from offices in Pune and New Delhi.
- Farm-machinery certification & homologation
- SMAM / state subsidy empanelment
- Manufacturing & supply chain