Founder Diaries · Problem Solving
By Sonal Sahani · ISIPCA Versailles 8 min read Updated July 2026
Spraying over a bad smell is why it keeps coming back. Every cabin odour has a source, and each source has a different fix. Here is how to identify what your Sierra EV actually smells of, deal with it properly - and the three smells you must never cover up.
Quick answer - read this first
Why does my Tata Sierra EV smell bad even after using a freshener? Because fragrance sits
on top of a smell - it does not remove it. The source is still there, so the odour returns within hours.
Identify the smell first using the table below, fix that specific source, and only then add scent -
Sea Breeze is a good odour-cutter for a electric Sierra like the Sierra EV.
Important: a smell of
fuel, something sweet and syrupy, or burning is a mechanical problem, not a freshness problem. Do not mask those - get the car checked.
The short answer for a Sierra EV
Musty smell when the AC starts? That is the AC evaporator and cabin filter - the single most common cause.
Sour, food or pet smell? Something organic is in the carpet, seats or under a seat. Find and clean it.
Straight answer
Why does the smell in your Sierra EV keep coming back?
Because you have been treating the symptom. Fragrance is additive - it layers a pleasant smell over an unpleasant one. For a few hours you get perfume; after that you get perfume and the original smell, which is worse than either. In a electric Sierra like the Sierra EV, the source is almost always one of five things - and four of them you can fix yourself in an afternoon.
Odour diagnosis
Match the smell in your Sierra EV to its source
| What it smells like |
Almost certainly |
The fix |
| Musty, like a damp cupboard - worst when AC starts |
Mould on the AC evaporator + old cabin filter |
Replace the cabin filter; have the AC system cleaned |
| Sour, slightly sweet, milky |
Spilled milk or a drink soaked into carpet |
Find it, shampoo the area, dry it fully |
| Old food, oily |
Wrappers, crumbs or a forgotten container under a seat |
Remove, vacuum deeply, wipe surfaces |
| Animal, musky, "wet dog" |
Pet hair and dander in upholstery |
Vacuum with a rubber brush, shampoo seats |
| Sweaty, gym-bag |
Kit, shoes or damp towels stored in the cabin or boot |
Take them out; wash mats; air the car |
| Damp, earthy after monsoon |
Water in the footwell or damp mats |
Dry mats in sun; check for leaks and blocked drains |
The most common culprit: your AC
If the smell is strongest in the first thirty seconds after you switch on the AC and then fades, you have found it. Moisture collects on the evaporator inside the dashboard, and in a warm, humid Indian climate that becomes a home for mould. The cabin filter then holds and recirculates it. No amount of fragrance in the Sierra EV fixes that - the air is being pushed through the problem before it reaches you.
1
Fix 01
Replace the cabin filter
Cheap, quick, and the single highest-impact thing on this page. If yours has not been changed in a year, it is holding every smell your Sierra EV has met - smoke, food, damp, all of it.
2
Fix 02
Have the AC system cleaned
Any decent service centre can clean the evaporator and ducting. Worth doing once if the musty smell is well established - and it makes a bigger difference than people expect.
3
Fix 03
Dry the system before you park
A habit worth building: switch the AC compressor off but leave the fan running for the last two minutes of a drive. It dries the evaporator so mould has less to work with. Free, and it stops the problem returning.
Food, pets and damp - the organic smells
Everything else on the list has one thing in common: something organic is sitting in your cabin. Milk in a carpet, crumbs under a seat, pet dander in the upholstery, a damp mat after monsoon. These smells are produced by bacteria, and bacteria do not care how nice your perfume is. Find the source, clean it, dry it completely - damp is what turns a small problem into a permanent one - and only then reach for fragrance. In a Sierra EV with a big boot or a third row, check the areas nobody looks at: under seats, seat rails, the boot floor and the spare-wheel well.
Please read this bit
Three smells you must never cover up.
Petrol or diesel inside the cabin can mean a fuel leak. A sweet, syrupy smell often means leaking coolant. Burning, hot plastic or electrical smells can mean wiring or brake trouble. These are mechanical faults, some of them dangerous. Do not put a freshener over them - get the Sierra EV to a mechanic. Fragrance is for a healthy car.
Now scent it - and make it stick
Once the source is gone and the cabin is dry, fragrance finally does what it is meant to do. For a electric Sierra like the Sierra EV, use a fresh odour cutter rather than something sweet - sweet scents sitting on a lingering smell is what creates that cloying, "hiding something" effect. Start with Sea Breeze, with Icy Mint as the alternative.
S
Spray
For the reset after cleaning
Once the Sierra EV is clean and dry, a few pumps resets the whole cabin - and gives you an on-demand tool for the next time someone brings biryani in. Alcohol-free, so no solvent hit on top.
H
Hanging
For the weeks in between
A hanging holds a gentle baseline so the cabin never drifts back toward stale. This is the part most people skip, and it is why smells seem to "return" even after a good clean.
Odour-cutting scents - Spray or Hanging
From ₹449. Fresh cutters are marked - tap any name to shop:
| SOSA scent |
Character |
Best for |
| Lemon |
Bright citrus that cuts odour (odour cutter)
|
Food smells and everyday staleness |
| Jasmine |
Soft mogra floral |
A gentle finish once the cabin is clean |
| Lavender |
Calming French lavender |
Soft cover for a family cabin |
| Sandalwood |
Creamy Indian sandalwood |
Warm cover for a clean cabin |
|
Icy Mint ★ |
Cool cornmint + peppermint (odour cutter)
|
Damp, stale and sweaty cabins |
| Vetiver (Khus) |
Dry earthy khus (odour cutter)
|
Pet and musty smells - earthy, not sweet |
|
Sea Breeze ★ |
Airy modern aquatic (odour cutter)
|
A just-aired-out clean feel |
| Oud (Assam) |
Deep naturally-derived agarwood |
Stubborn odours needing real depth |
| Mysore Orange Blossom |
Neroli, expensive-hotel floral |
A clean, costly-smelling finish |
| Oud + Lemon combo |
Fresh cutter + deep cover |
Stubborn odours, two-scent approach |
| 3-Spray Discovery Set |
Three travel minis |
Testing what works in your cabin |
Perfume over a bad smell gives you both smells. Find the source - then the scent finally works.
— Sonal Sahani, SOSA
After the clean, for your Sierra EV
Sea Breeze to cut odour, a hanging to hold it - or the Oud + Lemon combo at ₹949.
Shop Sea Breeze →
The full range
The fresh cutters - Lemon, Icy Mint, Sea Breeze and Vetiver (Khus) - are what we would use on a cabin that has had an odour problem. Oud gives real depth for stubborn cases, and Sandalwood, Jasmine, Lavender and Mysore Orange Blossom are lovely once the cabin is genuinely clean. Pairing a cutter with a deeper scent is the strongest approach - which is what the Oud + Lemon, Jasmine & Lemon, Sandalwood & Oud and Jasmine & Lavender combos are built for. The 3-spray Discovery Set lets you test what actually works in your own cabin. All alcohol-free.
A note from Sonal
The most common complaint I hear is "your scent stopped working". Nine times out of ten the scent is fine - there is an untreated smell underneath it, and the two are now fighting in a sealed cabin. That combination smells worse than the original problem.
So I would rather you did the boring part first: find it, clean it, dry it. Check the cabin filter. Then let a fresh scent do its job on clean air. And if you ever smell fuel, something sweet and syrupy, or burning - please do not reach for a freshener at all. Go to a mechanic. That is a car problem, not a fragrance problem.
Frequently asked questions
Why does my Tata Sierra EV still smell bad after using a freshener?
Because the source is still there. Fragrance layers over an odour rather than removing it, so within hours you smell both. Identify the source - most often the AC evaporator and cabin filter, or something organic in the carpet - fix it, then scent.
Why does my car smell musty when I turn on the AC?
Moisture on the AC evaporator encourages mould, and the cabin filter recirculates it. Replace the filter, have the system cleaned, and get into the habit of running the fan without the compressor for the last couple of minutes of a drive to dry it.
Which scent is best for covering bad smells?
Are there smells I should not cover with a freshener?
Yes. Fuel or diesel inside the cabin, a sweet syrupy smell (often coolant), and any burning or hot-plastic smell are mechanical faults - some potentially dangerous. Get the car checked rather than masking them.
Will a car perfume remove the smell permanently?
No. SOSA car perfumes freshen and mask - the cleaning removes. Use them as the finishing and maintenance step once the source is dealt with, and the cabin stays fresh instead of drifting back.
Find it. Fix it. Then scent it.
Stop covering the smell in your Tata Sierra EV - and start finishing the job. Alcohol-free. No headache.
Alcohol-free car perfume · fresh odour-cutting scents · Spray to reset, Hanging to hold · from ₹449, or the Oud + Lemon pair at ₹949 · made in India by an ISIPCA Versailles perfumer · a portion of every order supports girl-child education through Nanhi Kali.
Shop Sea Breeze → Get the Oud + Lemon pair
Continue the read
Odour-cutting picks
Editorial standards & safety note
About this guide: Written by Sonal Sahani, ISIPCA Versailles-trained founder and perfumer at SOSA Home & Body. SOSA car perfumes freshen and mask odours - they do not remove the source and are not cleaning, disinfecting or air-purifying products.
Safety: smells of fuel, coolant (sweet and syrupy) or burning/electrical origin may indicate a mechanical fault and should be inspected by a qualified mechanic, not masked. Car names describe the cabin only; SOSA is an independent fragrance brand not affiliated with any car maker. Prices correct as of July 2026.
