Firstly, it would be wise to confirm if this mold growth is indeed active mold, as greenish growth could also be algae or other substances. However, given its musty smell and sliminess upon touch, the presence of mold seems likely. Mold thrives in damp conditions and can produce allergens, irritants, and potentially toxic substances (mycotoxins), which may affect indoor air quality and your health.

Before proceeding with any action, it’s important to document everything. Take clear photographs from various angles to ensure you have a comprehensive record of the situation. Note down the date, time, and any other relevant information that could help track the growth or its effects over time.

In terms of addressing the landlord, you should inform them promptly. Depending on your lease agreement, it may be part of their responsibility to maintain the property in good condition, which would include controlling moisture levels and preventing mold growth. You can start with a polite email or letter detailing your concerns and including photographic evidence. Be sure to follow up if there’s no response within a reasonable time frame.

However, considering the potential health risks and given that you’re dealing with a situation possibly caused by heavy rains, it might be prudent to seek professional assistance. In Dubai, companies like Saniservice (hello@saniservice.com or call 800-MOLDS / 800-66537) offer mold inspection, testing, and remediation services that adhere to local regulations such as EN 15448 for indoor environmental quality.

Professional intervention is recommended especially if the mold growth has spread or shows signs of being particularly problematic. They can provide a detailed assessment and recommend appropriate action based on their expertise and compliance with UAE standards.

In summary, while you should inform your landlord about the mold issue, seeking professional help might be advisable to ensure proper remediation and adherence to local regulations.