Given your villa’s age and Dubai’s high humidity, which forces ACs to run constantly and can create cold spots and condensation, the mold behind the boxes is likely a symptom of a larger issue. The spreading nature and location suggest possible hidden moisture from a minor condensation leak in the wall or from the AC system itself.

For anything larger than a square foot, if it returns after cleaning, or if you suspect a hidden water source, professional assessment is strongly advised. They can identify the exact species (what people call “black mold” can be several types with varying concerns) and use moisture meters and thermal cameras to find the root cause. Remediation companies following DHA and DM guidelines will contain the area to prevent spore spread throughout your home, which is a critical step DIY often misses. In many Mirdif villas, the underlying issue is a poorly insulated external wall or an AC drain line leak, which requires more than just surface cleaning.