An eruption of Indonesia’s Mount Anak Krakatau caused five airports to suspend flight operations on Sunday, affecting hundreds of flights at Jakarta’s main airport, after some school activities and fishing were halted.

The suspension has affected 301 flights, including 58 international flights, airport operator Angkasa Pura said in a statement. Singapore Airlines said it had cancelled flights to and from Jakarta for the rest of the day.

Anak Krakatau, which is roughly halfway between Java and Sumatra in Indonesia’s vast island chain, has ⁠been erupting since late on Friday, with volcanic ash detected at the airport early on Sunday, the transport ministry said.

Passengers stuck at Soekarno-Hatta international

Ash reached as high as 20,000 feet (6,000 metres) on the Java side of the volcano and 50,000 feet (15,000 metres) on the Sumatra side and some parts of Banten province in Java, meteorological agency BMKG posted on its website.

After one domestic flight was cancelled, Suhardi, 58, made his way to Soekarno-Hatta, hoping to catch a connecting flight in the morning for a business trip to Samarinda on the Indonesian part of Borneo island.

“I thought Jakarta-to-Samarinda still available - apparently it is also cancelled,” Suhardi, who goes by one name, told Reuters.

French national Eloan Tasset, 21, got a text from Batik Air that his flight to his holiday destination of Manado in North Sulawesi had been delayed, but he said it was unclear how long the delay would be.

“If they tell me my flight is cancelled, I think I’m going to try to find a hotel in Jakarta,” he said.

The airport ⁠operator said it was providing food and light refreshments for affected passengers and buses to hotels, in coordination with the airlines.

The disaster mitigation agency BNPB said it would conduct a weather modification operation, which could include cloud-seeding, on Sunday 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,” BNPB chief Suharyanto told a press conference.

BNPB “urges the public to remain calm while increasing vigilance. In the event of ashfall, people are advised to wear masks and eye ⁠protection, reduce outdoor activities, cover water sources and exercise caution when driving, as volcanic ash can reduce visibility,” said spokesperson Berton Panjaitan.

Ferries in Sunda Strait were operating normally, the transport ministry said, urging vessels to stay at least 3 km (2 miles) away from Anak Krakatau’s crater and remain vigilant for volcanic hazards, including volcanic ash and other ejected materials.

Several schools cancelled activities on ⁠Saturday after students and residents suffered eye irritation from the ash, while fishermen cancelled fishing trips, local media outlet Kompas reported.Indonesia sits on the Pacific “Ring of Fire”, where earthquakes and volcanic eruptions are frequent. Anak Krakatau has been on alert level 3, the second-highest, since July 2.

The disaster mitigation agency said there was no imminent risk ⁠of tsunami from the volcano. A tsunami in 2018 caused by Anak Krakatau eruptions killed more than 400 on Java and Sumatra.

Anak Krakatau, which means child of Krakatau, emerged a century ago from the area once occupied by Krakatau, then known as Krakatoa. The older volcano destroyed itself in mass eruptions in 1883, which killed more than 36,000 people in a series of tsunamis.