Indonesia halted operations at eight airports on Sunday, including its main international hub, due to an ash cloud from the Anak Krakatau volcano. The eruption, which occurred on Saturday, produced lava and booming sounds heard up to 435 miles (700km) away, according to Indonesia’s geology agency. The event also disrupted school activities and fishing. Two more eruptions were recorded on Sunday, intensifying the situation.

Ash was detected in the airspace around Soekarno-Hatta international airport near Jakarta, leading authorities to suspend operations. The airport remained closed to flights until 9.30pm local time on Sunday. The suspension affected hundreds of flights, including international ones, as reported by the airport operator, Angkasa Pura. Singapore Airlines confirmed it had cancelled flights to and from Jakarta for the rest of Sunday. Qantas also reported disruptions to several services, including cancellations to and from Jakarta.

Volcanic ash poses significant risks to aviation, damaging jet engines and clogging fuel and air systems. It can also damage pilots’ windscreens. The meteorological agency BMKG noted that ash reached as high as 6,000 metres (20,000ft) on the Java side of the volcano and 15,000 metres on the Sumatra side, affecting parts of Banten province in Java. Schools and fishing activities were impacted, with several schools cancelling activities after students and residents experienced eye irritation, as reported by local media outlet Kompas.

The disaster mitigation agency BNPB announced plans for a weather modification operation, which could include cloud-seeding to promote rain. BNPB chief Lt Gen Suharyanto stated that heavy rain could wash away the volcanic ash, alleviating disruptions. The transport ministry reported that more than 22,000 passengers and 209 flights were affected, particularly those bound to and from Singapore. Other affected international routes included Doha, Sydney, and Kuala Lumpur. At least 16 domestic flights to Bali were also cancelled, according to local airport authorities.

Anak Krakatau, meaning 'child of Krakatau,' is located in a strait separating Java and Sumatra. The volcano has been sporadically active since emerging from the sea in the caldera formed after the 1883 eruption of Mount Krakatau, one of the deadliest and most destructive volcanic eruptions in human history, which killed about 35,000 people. Port authorities warned ships passing through the strait to avoid areas within two miles of the volcano and to remain vigilant.