By September, most Kolkata cars have spent three or four months being splashed, soaked, parked wet and driven through standing water. The rain eases, but what it left behind — damp in the cabin, mineral spots on the glass, grime in the wheel arches — keeps working on the car. September is the month to deal with it.
Why September deserves its own checklist
Kolkata's monsoon is not just rain. It is waterlogged roads around Thanthania and parts of Salt Lake, splashes of muddy water on every drive, cars parked damp in closed basements for days, and humidity that never quite lets the cabin dry. A car can look fine from the outside in September and still be carrying the season: damp under the carpets, minerals on the glass, mud packed into the arches.
None of this is dramatic on its own. Together, left through October and into winter, it is how a car starts to smell old, how glass gets hazy and how small rust spots become body-shop bills. A few hours of attention now prevents most of it.
1. The cabin: find the damp before you fight the smell
The "monsoon smell" is almost always moisture trapped somewhere it cannot evaporate. Wet shoes and umbrellas, a door seal that lets in a little water, the AC drain blocked with debris — the result is the same: damp carpet underlay and mats, and mould spores that the AC then circulates.
- Take every mat out. Rubber mats can be washed and dried in the sun. Carpet mats need vacuuming, cleaning and full drying before they go back.
- Press the carpet. Rear footwells and the boot floor are where water collects unnoticed. If it feels cool and damp, it is wet underneath.
- Dry it properly. Windows down on a dry, sunny day, doors open where safe, absorbent towels pressed into the carpet. A wet-and-dry vacuum helps.
- Clean the AC vents and check the cabin filter. A clogged, damp cabin filter is a common source of the smell. Our car AC service guide covers when to replace it.
- Then deal with the odour. Once dry, an odour treatment actually works. Before that it just masks.
If you would rather not spend a Sunday on it, an interior deep clean covers vacuuming, vents, door pads, seats and an odour check in your own parking slot.
2. The paint: water spots, film and fallout
When rainwater dries on a car, it leaves behind whatever it was carrying: dissolved minerals, soot from the air, residue from the road. These show up as spots and a dull film. On a hot afternoon, the spots can etch into the clear coat and become permanent marks.
The fix is a thorough wash followed by protection. Wash panel by panel with fresh solution and clean microfibre. Pay attention to the lower third of the car — doors, sills, bumpers — where muddy spray has been landing for months. Do not scrub dried mud dry; soften it first. After washing, run a clean hand over the paint inside a thin plastic bag. If it feels gritty, the surface has bonded contamination that needs decontamination before any wax or coating.
For paint that has lost its gloss, see our guide to rubbing and polishing. For long-term protection before the dusty months, ceramic coating is worth considering now, while the paint is clean and the weather is drier.
3. Wheel arches, sills and the underside
Mud thrown up by the tyres packs into the wheel arches, along the sills and behind the bumpers. Packed mud holds moisture against metal for weeks. That is where rust starts on Indian cars, not on the roof.
- Look inside each wheel arch with a torch. Packed brown deposits should be softened and removed.
- Check the drain holes along the bottoms of the doors. If they are blocked, water sits inside the door.
- Heavy underbody cleaning or anti-rust treatment belongs at a service centre with a lift. If the car went through deep water this season, have the underside inspected.
4. Glass, wipers and seals
Months of wiper use on gritty water wear the blade edge and leave fine arcs on the windscreen. Inside, the glass collects a greasy film from damp air and the cabin plastics. Both reduce visibility just as winter fog arrives.
- Replace wiper blades that streak or judder.
- Clean the inside of the windscreen with a dedicated glass cleaner and two microfibre cloths — one to clean, one to buff. Our streak-free glass guide explains the method.
- Wipe the door and boot rubber seals. Grit in the seals wears them and lets water in next season.
5. Seats and upholstery
Fabric seats absorb moisture from damp clothes and humid air all season. If a seat feels slightly cool and clammy, or there are faint tide marks where a wet umbrella was left, the foam underneath may still be holding water. Leave the car open in dry weather, vacuum the seats slowly with a brush attachment to lift dust that has bonded with moisture, and treat any marks with an upholstery cleaner applied to a towel rather than sprayed directly onto the seat. Leather seats need the opposite care: monsoon humidity followed by a dry winter can make them crack, so clean and condition them now. Our seat cleaning guide goes through fabric and leather separately.
6. Battery terminals and electrical contacts
Humidity encourages corrosion on battery terminals — the white or greenish crust you sometimes see around the clamps. It increases resistance and is a common reason for slow starts on the first cool mornings. Have the terminals cleaned and checked at your next service, and if the car has been reluctant to start, have the battery tested before winter rather than discovering the problem in fog at 7 am.
7. Rust spots and stone chips
Walk around the car in good light and look at the bonnet's leading edge, the front bumper, the lower doors, the boot lip and around the number plates. Stone chips that have had water in them for four months may show a small orange dot. Treated early, that is a touch-up job. Left, it creeps under the surrounding paint.
8. Under the bonnet and in the boot
Open the bonnet and look for leaves and debris in the scuttle panel below the windscreen — blocked drains there send water into the cabin. In the boot, lift the floor and check the spare wheel well. Water collects there unseen.
A simple post-monsoon schedule
Keeping it clean through winter
Once the car is reset, the next problem is dust. October to February is Kolkata's dusty season, with construction dust, traffic soot and fog that turns dust into a damp film. A regular wash routine keeps the reset you just did from being undone. Car Ninza's monthly plans wash the car on fixed weekdays in your own parking slot, with one full interior and exterior clean each month — so a damp-carpet problem is caught before it becomes a smell.
Not sure where to start? Book a free demo and our crew will look at the car with you, wherever it is parked.
