That damp-towel smell when you turn the AC on isn't the cabin filter. It's mould growing inside the evaporator. Ozone gets in where wipes can't.
The air conditioning evaporator sits deep inside the dashboard. Whenever it cools, it condenses moisture out of the air. In a tropical climate, the evaporator is wet for most of the year. Wet + dark + warm at the edges = mould.
Why a "cabin air filter replacement" doesn't fix it
The filter sits upstream of the evaporator. The smell is downstream, coming from the wet coils themselves. Replacing the filter masks the issue for a week, then it returns.
What ozone vent fogging does
We open the AC to its maximum recirculation setting, insert an ozone nozzle into the cabin air intake, and let ozone circulate through the ducting for 5 minutes. The ozone reaches every cubic millimetre of the evaporator and ducts, places wipes physically can't reach. Mould and bacteria are oxidised. The smell stops.
Add it as a ₹199–₹299 upgrade to any wash package. One treatment usually lasts the full season.