Which Car Modifications Are Legal in India? RTO Rules Explained

Legal status of common modifications

The legal principle: Section 52 of the Motor Vehicles Act

Section 52 prohibits altering a vehicle so that the particulars in its RC no longer match reality, unless you get prior permission from the registering authority. This is the rule that governs almost every modification question — the test is not 'does it look aftermarket' but 'does it change what's recorded in my RC or affect safety, noise or emissions compliance.'

Modifications you generally don't need approval for

• Seat covers, floor mats, sun shades, mobile holders, dash cams
• Same-size alloy wheels that match an OEM variant's spec
• Paint protection film (PPF) and ceramic coating (doesn't change the registered colour)
• Reversing cameras, parking sensors that don't alter the body
• Roof racks/carriers that don't exceed permitted dimensions

Modifications that need RTO approval or endorsement

• Change of colour (must be updated on the RC within 30 days; fines apply if not)
• Fuel-system conversion (CNG, LPG, or EV retrofit) — needs an approved kit and RC endorsement
• Engine replacement or re-mapping that changes rated power/emissions category
• Seating capacity changes (e.g., adding a third row)
• Alloy wheels of a significantly different size/offset than any listed variant

Modifications that are simply illegal, approval or not

Some changes are banned outright regardless of RTO permission because they violate central notifications on safety, noise or emissions:

• Bull bars, nudge guards and metal crash guards — banned nationwide since a 2017 MoRTH directive, as they worsen pedestrian injury and interfere with airbags
• Altered or after-market exhausts that exceed notified noise limits (typically around 80–90 dB depending on vehicle category)
• Pressure horns, sirens, and multi-tone horns not fitted by the OEM
• Window film beyond the Supreme Court-mandated visible light transmission limits (roughly 70% on front/rear windscreen, 50% on side windows, though exact figures are set by rule and vary by notification)
• Neon undbody lighting and non-standard headlamp/tail-lamp colour changes
• Non-standard number plates (fancy fonts, 3D plates, or plates not matching the High Security Registration Plate — HSRP — format)

Penalties and enforcement

Fines vary by state under the amended Motor Vehicles Act, but unauthorised structural changes commonly attract fines from ₹5,000 up to ₹10,000, with the possibility of the RC being suspended until the vehicle is restored to its approved specification. Traffic police in most metro cities now also use spot checks specifically targeting bull bars, tinted glass and altered exhausts, especially around festival and enforcement drives.

Before you modify: a quick checklist

1. Check whether the change affects colour, engine, fuel type, chassis or seating — if yes, you need RTO approval first.
2. Confirm the part is from an RTO/ARAI-approved supplier, especially for CNG/LPG kits.
3. Get any approved change endorsed on the RC within the required window (commonly 30 days).
4. Inform your insurer and add the relevant cover (see our guide on insurance and modifications).
5. When in doubt, ask your RTO or a reputed dealer service centre before spending money on the mod.