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Vehicle Modifications: Legal Changes, CNG Kit and RC Entry
Under section 52 of the Motor Vehicles Act, you must not alter your vehicle so that it no longer matches the details on its RC, as the manufacturer specified them. The main exceptions are fuel conversion with an approved kit, such as CNG or LPG, and conversion into an adapted vehicle for a person with a disability. After either, the change must be recorded on your RC. An owner who makes a change that isn't allowed can be fined ₹5,000 for each alteration under section 182A(4), and window films that cut the light below the legal limits break rule 100(2).
- Main law
- Section 52, Motor Vehicles Act
- Penalty
- ₹5,000 per alteration and/or up to 6 months (182A(4))
- Report change
- Within 14 days, to the RTO
- RC entry fee
- Half the registration fee (₹300 for a car)
- Glass
- 70% light (front, rear), 50% (sides)
On this page
What does section 52 of the Motor Vehicles Act say?
| Part | What it says, in plain words |
|---|---|
| 52(1) | No owner may alter a vehicle so that the details in its RC differ from those the manufacturer originally specified. |
| 52(1), first proviso | Modifying the engine to run on another fuel or energy source (battery, CNG, solar power, LPG or other) by fitting a conversion kit is allowed, on conditions the Central Government sets. |
| 52(1), proviso added in 2019 | The Central Government may set specifications and conditions for approval and retrofitment. For such an alteration, the manufacturer's warranty is not void. |
| 52(2), as replaced in 2019 | Anyone may alter their own vehicle into an adapted vehicle, with the later approval of the registering authority, on prescribed conditions. |
| 52(3) | If an alteration is made without the registering authority's approval, the owner must report it within 14 days to the registering authority where they live, with the RC and the fee, so the details are entered. |
| 52(5) | A person holding a vehicle under a hire-purchase agreement needs the registered owner's written consent to alter it. |
| Explanation | "Alteration" means a change in the structure of a vehicle that results in a change in its basic feature. |
So the test is: does the change alter the structure or a basic feature, or make the RC details wrong? If yes, it is either allowed with an RC entry (the cases below) or not allowed at all.
What changes are allowed, and which need an RC entry?
Fuel conversion (CNG, LPG, electric)
- Allowed, but only with a conversion kit that meets the Central Government's conditions.
- Needs an RC entry. The fuel on the RC must match the vehicle.
- Details in CNG, LPG and electric conversion.
Adapted vehicle for a person with a disability
- Allowed under section 52(2), with the registering authority's approval afterwards, on prescribed conditions.
- A vehicle being converted into an adapted vehicle can get temporary registration, according to the Ministry.
- See adapted vehicles and the licence.
Other structural changes
- A change to the structure or a basic feature that isn't one of the permitted cases is not allowed, even if it is reported.
- Anything recorded on your RC, such as the body colour if your RC shows it, must match the vehicle. If you change it, ask the RTO to record the change.
- Not sure? Ask the RTO before making the change, not after.
How do CNG, LPG and electric conversions work?
Section 52 allows a conversion kit for CNG, LPG, battery or another fuel, on conditions set by the Central Government in the Central Motor Vehicles Rules. The Ministry has also notified rules for particular conversions:
| Conversion | Notification |
|---|---|
| Replacing a BS-VI diesel engine with a new CNG engine | G.S.R. 625(E), 11 Aug 2022 |
| Fitting a hybrid or electric system | G.S.R. 167(E), 1 Mar 2019; must comply with AIS 123 |
Gas vehicles still need a valid PUC certificate. Tell your insurer about the conversion as well, so the policy describes the vehicle correctly.
How do you get the change recorded on your RC?
YouRTO / VAHANFee
- Check with the RTO that the change is allowed for your vehicle
- Is it a permitted change (approved kit or adapted vehicle)?No: don't make it; an unpermitted alteration is an offence
- Have the change made, and keep the fitter's papers
- Within 14 days, report it to the RTO with the RC
- Pay the fee for recording the alteration
- The alteration is entered on the RC and on VAHAN
The central fee for recording an alteration (rule 81) is half the registration fee:
| Vehicle | Fee |
|---|---|
| Motorcycle | ₹150 |
| Car or 3-wheeler, private | ₹300 |
| Light, transport | ₹500 |
| Medium vehicle | ₹500 |
| Heavy vehicle | ₹750 |
States add their own service and smart-card charges, so ask the RTO for the total and its document list. ✔ You'll know it worked when the vehicle details on VAHAN or mParivahan show the change.
What about tinted glass, lights, horns and alloy wheels?
| Item | Fine (Delhi) | Rule |
|---|---|---|
| Tinted glass or dark film | ₹500; ₹1,500 repeat | Rule 100(2): windscreen and rear window must let through at least 70% of light, side windows at least 50% |
| Coloured lights on the vehicle | ₹500; ₹1,500 repeat | Delhi rule 97(2) |
| Using high beam where not allowed | ₹500; ₹1,500 repeat | Rule 112(4)(c), as listed by Delhi Traffic Police |
| Pressure horn | ₹5,000; ₹10,000 repeat | Sections 39 and 192, as listed by Delhi Traffic Police |
| Fancy or defective number plate | ₹5,000; ₹10,000 repeat | Rules 50 and 51 |
| Exhaust cut-out (gases bypass the silencer) | ₹1,000; ₹2,000 repeat | Section 194F |
- Glass: the front windscreen of vehicles other than two-wheelers and tractors must be laminated safety glass (rule 100(3)). A film that brings the light below 70% or 50% breaks rule 100(2).
- Lights: rule 105 sets the headlamps, rear lamps, a white light on the number plate and a reversing lamp. The driving regulations also ban air horns, multi-tone horns and exhaust cut-outs; see horn and lights rules.
- Alloy wheels: we found no central rule or official notice that names alloy wheels. Whether a wheel or tyre change counts as an alteration depends on whether it changes the vehicle's structure, a basic feature or the details on the RC. Ask your RTO before changing the wheel or tyre size.
- Number plates: see HSRP number plates.
The fines above are the Delhi Traffic Police's settlement amounts. Other states set their own; your challan shows your state's amount.
What are the penalties for illegal modifications?
You, the owner
Section 182A(4): an owner who alters a vehicle, including by retrofitting parts, in a way the Act or rules don't permit can get up to 6 months in prison, a fine of ₹5,000 per alteration, or both.
Manufacturer, importer or dealer
Section 182A(1): one who sells, delivers or alters a vehicle in breach of the construction rules faces up to 1 year, a fine of ₹1 lakh per vehicle, or both, unless they told the buyer how the vehicle broke the rules. Selling a non-compliant notified critical safety part: up to 1 year or ₹1 lakh per part, or both (182A(3)).
What can go wrong, and how do you fix it?
| Your situation | What it usually means | What to do |
|---|---|---|
| CNG kit fitted but not on the RC | The alteration was not reported | Report it to the RTO at once with the RC, the fitter's papers and the fee. |
| RTO won't record the kit | The kit isn't approved for your model | Ask the fitter for the approval papers, and ask the RTO what it needs to accept the conversion. |
| Challan for tinted glass | Film below 70% or 50% light | Remove the film and pay or contest the challan. See check and pay a challan. |
| Buying a used vehicle with changes | The RC may not match the vehicle | Compare the fuel and other details on VAHAN with the vehicle before you pay. See used vehicle checklist. |
| You hold the vehicle under a hire-purchase agreement | Someone else is the registered owner | Get the registered owner's written consent before any alteration (section 52(5)). |
Frequently asked questions
Is it legal to fit a CNG kit to my petrol car?
Yes, if the kit meets the Central Government's conditions and the conversion is recorded on your RC.
How soon must I tell the RTO about an alteration?
Within 14 days of making it, with the RC and the fee (section 52(3)).
What is the fine for an illegal modification?
Up to ₹5,000 for each alteration and/or up to 6 months in prison under section 182A(4). Specific items such as tinted glass or pressure horns have their own fines.
Is a sun film allowed on car windows?
Rule 100(2) requires at least 70% light through the windscreen and rear window and 50% through the side windows. A film that brings it below that is an offence.
Are alloy wheels legal?
No central rule we found names them. Ask your RTO, especially if the wheel or tyre size changes.
Does a retrofit void my warranty?
Not for an alteration or retrofitment approved under section 52, according to the 2019 amendment.
How much does the RTO charge to record the change?
Half the registration fee: ₹300 for a private car and ₹150 for a motorcycle, plus state charges.
Sources
- MoRTH – Motor Vehicles Act, 1988, Chapter IV: section 52 (accessed 26 Oct 2026)
- Motor Vehicles (Amendment) Act, 2019 – Gazette text (Transport Department, Chhattisgarh): sections 52, 182A and 194F (accessed 26 Oct 2026)
- MoRTH – Central Motor Vehicles Rules, Chapter V: rules 100, 102 and 105 (accessed 26 Oct 2026)
- Delhi Traffic Police – traffic violations and penalties (accessed 26 Oct 2026)
- Transport Department, Andhra Pradesh – registration fees: recording an alteration (accessed 26 Oct 2026)
- PIB – Lok Sabha reply, 28 Nov 2024: G.S.R. 625(E) and G.S.R. 167(E) (accessed 26 Oct 2026)
- MoRTH Year End Review 2025: alterations for Divyangjan (accessed 26 Oct 2026)
Page history: 26 Oct 2026: first published.