Indonesia's Soekarno-Hatta International Airport, the country's busiest aviation hub located outside Jakarta, suspended flight operations on Sunday after volcanic ash from the erupting Mount Anak Krakatau drifted across the capital and surrounding regions. The suspension, which was extended multiple times throughout the morning, remained in place until 1:30pm local time (06:30 GMT), affecting 209 flights and stranding more than 22,000 passengers. Cancelled and delayed routes included international services to and from Singapore, Kuala Lumpur, Guangzhou, Hong Kong, Doha and Sydney. Singapore Airlines alone cancelled 19 flights between Singapore and Jakarta on Sunday.

Anak Krakatau, which translates as "Child of Krakatau" and sits in the Sunda Strait between Indonesia's two most populous islands, Java and Sumatra, began erupting late on Friday. By Sunday, two further eruptions had been recorded, producing fountains of lava and booming sounds audible up to 700 kilometres away. Authorities detected ash plumes reaching as high as 6,000 metres on the Java side of the volcano and up to 15,000 metres on the Sumatra side. A second ash cloud tracked by the Darwin Volcanic Ash Advisory Centre in Australia reached an altitude of 50,000 feet, drifting westward and covering parts of Banten, Lampung and Bengkulu provinces. A "paper test" conducted at the airport in the early hours of Sunday confirmed the presence of ash in the airspace, prompting the flight suspension to be extended. Indonesia's health minister urged residents in affected areas to stay indoors, wear face masks, and take precautions against respiratory, eye and skin irritation. Several schools cancelled activities on Saturday, and fishermen suspended trips as ash fell across the region.

Authorities confirmed there is no tsunami risk from the current eruption, a reassurance that carries particular weight given the volcano's recent history. In 2018, a partial collapse of Anak Krakatau's crater triggered a tsunami that killed more than 400 people along the coasts of Java and Sumatra. The volcano itself emerged from the sea in the 1920s, forming in the caldera created by the catastrophic 1883 eruption of Krakatoa — one of the deadliest volcanic events in recorded history, which killed more than 36,000 people. Indonesia sits on the Pacific Ring of Fire, a zone of intense seismic and volcanic activity, and has dozens of active volcanoes. Volcanic ash poses a recognised hazard to aviation, capable of damaging jet engines and severely reducing visibility, which is why civil aviation authorities prioritised safety in extending the suspension. Director General of Civil Aviation Lukman F Laisa said authorities would continue monitoring the situation in coordination with airlines and meteorological agencies.