Indoor Air Quality Alert: Bangkok and Central Thailand flooding

What is the location of the flooding?

As of September 30, 2026, the September 2026 Thailand floods are centered on the capital, Bangkok, and continue to affect large parts of central and eastern Thailand. The flooding followed heavy, accumulated rainfall between September 16 and 28. River overflow and higher discharge from the Chao Phraya Dam made it worse (1).

Bangkok received about 320 mm (12.6 inches) of rain in three days. That is nearly as much as the low-lying city usually gets in all of September. The rain came from an area of low pressure that moved northwest up the Gulf of Thailand and then stalled over central Thailand for about two days (2).

Canals across Bangkok have burst their banks and flooded the roads next to them. City officials say the eastern part of the capital has been hit hardest (3).

Which cities or areas are affected by the flooding?

Flooding has affected 41 provinces, 214 districts, and more than 5,100 villages. About 927,400 households, or more than 2.5 million people, have been affected. At least 23 people have died nationwide since September 16, including four in Bangkok (4).

The following provinces and areas across Thailand are among those directly affected:

In Bangkok, about 329,000 households have been affected. Affected neighborhoods include:

Samut Prakan, home to Suvarnabhumi Airport, has reported the highest toll outside the capital, with 260,784 households affected and eight deaths.

What is the current containment status of the flooding?

As of September 30, 2026, floodwaters are receding in Bangkok, and recovery work is underway where water levels have dropped. Bangkok Governor Chadchart Sittipunt expects water to drain from major roads within two days. Other flooded areas may take up to a week to clear (5).

The heaviest rain ended when the low-pressure system moved northwest on Sunday, September 27. However, as of September 28, flooding was still ongoing in 28 provinces, and several areas reported rising or stagnant water levels (6).

Travel is still disrupted. Thai Airways cut about 30% of its planned departures from Bangkok and expects reduced service for at least three days. About 5,600 bags remain stranded at Suvarnabhumi Airport (7).

Are there any evacuation orders or alerts in place?

Bangkok authorities initially declared all 50 of the city's districts a flood disaster zone. On September 29, the designation was lifted in 21 districts and remained in place in 29. The declaration gives local organizations the authority to act quickly.

In Bangkok, nearly 6,000 people have moved into 234 evacuation centers. Outside the capital, 27 temporary shelters have opened in Sa Kaeo, and more shelters have been set up in Chanthaburi and Nakhon Ratchasima.

Rising reservoirs in an eastern province have also led to evacuations. More than 80,000 residents in flooded areas cannot leave their homes, and mobile kitchens and boats are delivering meals to them.

Residents are urged to stay home, and people living near canals should move their belongings to upper floors. Drivers are advised to move vehicles to higher ground, and free parking is available at MRT park-and-ride lots until October 2. Authorities warn that more rain could cause flash flooding, river overflow, and landslides, especially in low-lying areas and areas near waterways (8).

How can I protect myself from mold after flooding?

It’s important to take steps to prevent mold after a flood.

Before entering a flooded area, make sure it is safe and free from electrical hazards or structural damage.
Use protective gear: wear gloves, goggles, and a KN95/FFP2 mask to minimize exposure to mold spores.
If there is still standing water, remove it as quickly as possible. Use pumps, wet-dry vacuums, or buckets to extract the water.
Open windows and doors to facilitate air circulation and use fans, dehumidifiers, and HVAC systems to help dry the space. This step is crucial within the first 24-48 hours after flooding to prevent mold growth.
Remove and discard any items that have been severely damaged by floodwater and cannot be thoroughly cleaned and dried. This includes carpets, upholstered furniture, mattresses, and any other porous materials.
Thoroughly clean all hard surfaces with a detergent or cleaner suitable for mold remediation. Use a solution of 1.5 cups of bleach mixed with one gallon of water to disinfect nonporous surfaces. Never mix bleach with ammonia or other cleaning products, as the fumes are toxic.
Maintain an indoor relative humidity (RH) of 35-50%. High humidity promotes mold growth, so consider using dehumidifiers in damp areas.
Run a high-performance air purifier for mold, both during and after the mold removal work.
If the flooding and mold damage are extensive, consider contacting professionals specializing in mold remediation to ensure proper cleanup and restoration.

Remember, mold can pose health risks, so it's important to take these steps promptly and thoroughly. If you experience persistent mold-related health issues or have concerns about extensive mold growth, consult with a medical professional or a mold remediation specialist.