Indonesia halted operations at eight airports on Sunday, including its main international hub, affecting hundreds of flights as a result of an ash cloud from the Anak Krakatau volcano. This was reported by Qazaqyia.kz citing The Guardian.

Saturday's eruption, which produced lava and booming sounds that were heard up to 435 miles (700km) away, according to Indonesia's geology agency, also interrupted some school activities and fishing.

Two more eruptions were recorded on Sunday.

Ash was detected in the airspace around Soekarno-Hatta international airport near Jakarta, prompting authorities to suspend operations. They announced several extensions of the shutdown, keeping the airport closed to flights until 9.30pm local time on Sunday.

The suspension affected hundreds of flights, including international ones, the airport operator, Angkasa Pura, announced. Singapore Airlines said it had cancelled flights to and from Jakarta for the rest of Sunday.

The Australian flag carrier said there were "disruptions to a number of Qantas services, including cancellations to and from Jakarta today".

"Our meteorologists and operations teams are closely monitoring conditions in and around Jakarta and any impact on our operations," it said in a statement.

"Safety remains our highest priority. We have contacted affected customers and are providing assistance. Services will resume when conditions allow."

Volcanic ash can damage jet engines – baking on to hot internal parts and quickly wearing out turbine blades, as well as clogging fuel and air systems. It can also damage pilots' windscreens.

Ash reached as high as 6,000 metres (20,000 feet) on the Java side of the volcano and 15,000 metres on the Sumatra side and some parts of Banten province in Java, the meteorological agency BMKG said.

Several schools cancelled activities on Saturday after students and residents suffered eye irritation and fishers cancelled fishing trips, the local media outlet Kompas reported.

The disaster mitigation agency BNPB said it would conduct a weather modification operation, which could include cloud-seeding to promote rain.

"If it rains heavily enough, the volcanic ash that has been disrupting our daily lives since yesterday and continuing today will be washed away quickly," the BNPB chief, Lt Gen Suharyanto, told a press conference.

More than 22,000 passengers and 209 flights were affected, the transport ministry said, 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 cancelled, local airport authorities said.

Anak Krakatau, which means "child of Krakatau", sits in a strait that separates the islands of Java and Sumatra. The volcano has been sporadically active since it emerged from the sea in the caldera formed after the 1883 eruption of Mount Krakatau. That was one of the deadliest and most destructive volcanic eruptions in human history. About 35,000 people were killed.

Port authorities said ships passing through the strait were prohibited to go within a two-mile radius of the volcano and should be vigilant.