What is the location of the flooding?
As of January 21, 2026, the flooding event is affecting multiple regions across Indonesia. In Greater Jakarta (Jabodetabek), including East, Central, West, South and North Jakarta, widespread and intense rainfall has inundated neighborhoods and disrupted daily activities.
Flooding is also impacting Java’s northern coastal areas, particularly Pekalongan, Kudus, and Pati, where continuous heavy rainfall and rising river levels have caused significant disruptions to communities and infrastructure (1).
In East Java, several districts such as Lamongan and Sidoarjo continue to face persistent flooding. Water levels have not fully receded due to ongoing rainfall, inflow from nearby rivers, and unstable local weather patterns (2).
The flooding is linked to extreme rainfall, tidal influences, river overflows, and long-term land subsidence in low-lying northern Jakarta, all of which have slowed drainage and worsened flood conditions. In Central Java, additional inundation has occurred due to overflows from the Bremi and Meduri rivers, affecting railway lines and hindering transportation and emergency operations.
Which cities or areas are affected by the flooding?
The following cities, districts, and regions are reported as directly impacted:
- Jakarta
- Kelapa Gading and Gunung Sahari in North Jakarta
- Pekalongan, Central Java
- Kudus, Central Java
- Pati, Central Java
- Lamongan, East Java
- Sidoarjo, East Java
- Surabaya, East Java
- Malang, East Java
- Pasuruan, East Java
- Probolinggo, East Java
- Banyuwangi, East Java
- Madiun, East Java
- Mojokerto, East Java
- Jember, East Java
- Jombang, East Java
- Ngawi, East Java
- Pamekasan and Sumenep in Madura
- Yogyakarta (rail service disruptions)
What is the current containment status of the flooding?
As of January 21, 2026, containment efforts remain ongoing across affected regions. In Jakarta, extensive pumping operations involving more than 1,200 pumps helped reduce water levels, although tidal conditions have slowed full recession (3).
In East Java, flooding in Lamongan and Sidoarjo has not receded, with waterlogged conditions stable but persistent due to ongoing inflows and heavy rainfall (4).
In Central Java, approximately 85 percent of rail services have resumed, although some routes remain under speed restrictions due to lingering floodwater. Across Java, authorities continue to monitor river levels, reinforce drainage systems, and maintain emergency operations.
Are there any evacuation orders or alerts in place?
Evacuation measures vary across the affected regions. In Jakarta, authorities did not establish large-scale evacuation centers, although limited evacuations took place in several low-lying neighborhoods.
In Pekalongan City, a 14-day emergency response period was declared from January 17 to 31, 2026, during which thousands of residents were displaced and shelters were opened to accommodate them (5).
In East Java, districts such as Lamongan and Sidoarjo reported over 2,000 affected residents, most of whom have remained in their homes but continue to remain on alert due to persistent flooding.
Additionally, BMKG issued extreme weather warnings for various East Java regions from January 11 to 20, urging the public to remain vigilant in response to potential hydrometeorological hazards (6).
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.
