• An eruption of the Anak Krakatau volcano in Indonesia has led to the closure of major airports, stranding over 170,000 travelers and affecting more than 1,500 flights.
• The volcanic ash from the eruption has caused chaos in air traffic, with authorities unsure of how long the disruption will last due to changing wind directions at different altitudes.
• Efforts are being made to mitigate the impact of the volcanic ash, including cloud seeding for artificial rain and distributing breathing masks to the population in affected areas.

An eruption of the Anak Krakatau volcano has thrown air traffic in Indonesia into chaos with tens of thousands of people stranded on Java and Sumatra since the weekend and the two international airports in the capital Jakarta shut until at least Monday evening.

Authorities said on Monday that volcanic ash from the eruption will keep the airports, including the key Soekarno-Hatta airport, closed. Air traffic at five smaller airports in the island nation has also been at a standstill since the weekend.

More than 1,500 flights and around 170,000 passengers have now been affected, the Indonesian news agency Antara reported, citing Transport Minister Dudy Purwagandhi. While the airport on the Indonesian island of Bali, popular with tourists from around the world, initially remained open, the megacity of Jakarta is an important hub in Southeast Asia.

"Safety is our priority," Purwagandhi stressed. The changing wind directions at different altitudes made it difficult to predict how long the volcanic ash would disrupt air traffic.

Indonesia lies on the Pacific Ring of Fire, a zone of particularly intense volcanic and seismic activity. The South-East Asian archipelago has around 130 active volcanoes - more than any other country in the world.

Loudest noise ever recorded

The volcano, located in the Sunda Strait between the islands of Java and Sumatra, has been active again since Friday. The name Anak Krakatau, which means Child of Krakatau, was formed after the legendary eruption of the Krakatau volcano in 1883, which killed more than 36,000 people.

That explosion is considered the loudest noise ever recorded, according to the Guinness Book of World Records. It was so powerful that its thunder could still be heard thousands of kilometres away. A large part of the volcanic island at the time sank into the sea.

Anak Krakatau has also already triggered a deadly disaster: in 2018, after an eruption, part of the volcano slid into the sea and triggered a tsunami. More than 400 people died.

Artificial rain intended to help

After the latest eruption, authorities want to use so-called cloud seeding to trigger artificial rain. This is intended to wash the volcanic ash out of the atmosphere and off affected areas.

Efforts are also under way on land to deal with the ash: in Bandar Lampung on Sumatra, the city administration had several main roads sprayed with water to reduce dust exposure for the population.

In Jakarta and in parts of the badly affected Banten province, schools have been switched to remote learning until further notice. The BNPB disaster management agency distributed, among other items, breathing masks and deployed emergency forces to monitor the affected areas.

Health Minister Budi Gunadi Sadikin called on the public to remain calm, stay indoors as much as possible and protect their eyes and airways with masks and safety goggles. Health centres are also preparing for a possible increase in respiratory illnesses.