The small Anak Krakatau Volcano, located between Indonesia’s islands of Java and Sumatra, produced a powerful eruption lasting more than 24 hours at the beginning of September 2026. The eruption sent large amounts of gas and ash into the atmosphere, disrupting thousands of flights and deteriorating air quality in parts of the country, including Jakarta.
Images captured on September 5 by Landsat 8’s OLI and the VIIRS instrument aboard the Suomi NPP satellite showed volcanic gas and ash clouds spreading across a wide area. Indonesia’s meteorological agency reported that, as of September 6, the ash had reached 6,000 meters east of the volcano and 15,000 meters to the west. Because of the ash, eight airports in Java and Sumatra were temporarily closed; approximately 3,000 flights to and from the region were disrupted.
Ashfall affected settlements, particularly in Jakarta and other parts of West Java. The Indonesian Humanitarian Coordination Platform stated that volcanic ash poses a health risk to the respiratory tract, eyes and skin, and that it differs from particulate matter from peatland-fire smoke in the country in terms of its characteristics, distribution pattern and protective measures.
The continuous eruption weakened on September 6, but the volcano continued to intermittently spew ash and volcanic material. Airports reopened on September 8; Anak Krakatau has remained at the country’s second-highest alert level since the beginning of July.
Why it matters
The impact of this development extends beyond settlements around the volcano, affecting Indonesia’s air transport and daily life at the same time. While disruptions to flights show that volcanic ash is a risk that must be directly taken into account in transport planning and airport operations, exposure in Jakarta and West Java requires healthcare institutions and local authorities to continue issuing protection advisories to the public. The fact that the ash has different characteristics from peatland-fire smoke also shows that a one-size-fits-all approach cannot be applied under the same air pollution heading. Since the reopening of airports does not mean that the effects have ended, how long the intermittent eruptions will continue and when the alert level will change remain open questions.
Background
Again, FikirPilot is not a new name in the archive: we have published 3 reports mentioning this name in the last 90 days; the latest is dated September 6, 2026.