After the Mumbai Monsoon: Mould and Fungus on Car Seats, Roof Lining and Seatbelts

Why mould grows in cars after the Mumbai monsoon

Mould needs moisture and time. A Mumbai monsoon supplies both.

Average relative humidity at Santacruz climbs to 81% in July and August, and Colaba reaches 85%, according to IMD normals summarised on Wikipedia. For comparison, the US Environmental Protection Agency advises keeping indoor humidity below 60% to prevent mould. A closed car in July sits well above that for weeks.

The EPA also notes that damp materials dried within 24 to 48 hours usually won’t grow mould. In a car, they rarely dry that fast:

• Wet shoes and umbrellas soak floor mats, and the carpet under them stays damp

• Closed windows trap humid air, especially in covered parking with no sun

• Leaky door or windscreen seals let water in during heavy rain

• Leaves block sunroof or door drain holes, so water runs into the cabin instead of out

• A car that sits unused for days never gets the drying effect of running the AC

Fabric seats, roof linings and carpets are porous. Once mould gets into the foam or backing, surface wiping can’t reach it, which is why it keeps coming back.

Where to look for mould in your car

Check these spots, ideally in daylight with the doors open:

Not sure if it’s mould or dust? Mould tends to be fuzzy or powdery, grows in spots, smells musty and returns after wiping. Dust doesn’t.

When to call a professional

DIY handles light, surface mould. Call a professional if:

• Mould is in the roof lining (it sags if over-wetted) or under the carpets

• The musty smell remains after cleaning

• The car took in water during a flood or heavy rain

• Someone in the family has asthma or allergies

• Mould keeps coming back within weeks

A professional job reaches where home cleaning can’t. Our steam sanitisation interior clean treats seats, carpets, vents and trims with high-temperature steam, which uses very little water and kills mould on contact. You can see how the process works in our car steam cleaning guide for Mumbai and our car deep cleaning service in Mumbai.

If the main problem is smell rather than visible mould, read our guide to car smell removal in Mumbai, which goes through damp, smoke, food and AC odours one by one. Our car interior cleaning price guide shows what each level of cleaning typically costs.

Different surfaces need different treatment

The most common DIY mistake is cleaning everything the same way. Here’s what each material needs.

Leather deserves a special note. The white bloom on leather in Mumbai monsoons is often mould feeding on body oils and old conditioner. Cleaning it properly and then reconditioning matters, because leather left dry after cleaning cracks in the October heat that follows.

Find the source, or the mould comes back

The EPA makes the point plainly: clean mould without fixing the water problem, and it returns. In a car, check:

• Door and windscreen seals. Look for cracks, gaps or water marks on the trim below them.

• Drain holes. Sunroof drains and the bottom edges of doors have drain holes that leaves block. Clear them.

• Carpet under the mats. Press it with your hand after rain. If it’s wet, find where the water enters.

• The boot. Lift the floor and check the spare wheel well for standing water.

• AC drain. If water drips inside the cabin instead of under the car, the AC drain may be blocked. That’s a job for your service centre.

Monsoon car care tips to stop mould next year

• Switch to rubber mats in June. They hold water you can tip out, instead of soaking it into carpet.

• Bag wet umbrellas. Keep a plastic bag or tray for them.

• Use the AC. It dries cabin air. Running the fan for a few minutes with the AC off before you park helps dry the AC system.

• Drive the car. A car parked for weeks in a humid basement is a mould incubator. Start and drive it at least twice a week.

• Moisture absorbers. Dehumidifier bags or silica sachets under the seats help in long parking spells; replace them when full.

• Clean before and after. An interior clean in May removes the dirt mould feeds on, and another in October deals with anything that grew.

Our monsoon interior cleaning guide for Mumbai covers the full routine. Salt air and rain also attack the underbody, which is a separate job; see why Mumbai owners should ask about the undercarriage first.

Doorstep mould treatment across Mumbai

Royal Royce started in Mumbai in 2017, and monsoon interiors are part of every year here. We clean at your doorstep across Mumbai. Coatings and paint correction are studio jobs, with pick-and-drop so the car is collected and returned. Contact our Mumbai branch.

Sources

• Wikipedia, Climate of Mumbai (IMD humidity normals)

• US EPA, A brief guide to mould, moisture and your home