Cendy Rahmat never imagined he would experience volcanic ash while living in Jakarta.
Growing up in Yogyakarta near Mount Merapi, one of Indonesia's most active volcanoes, he was familiar with volcanic activity and had experienced eruptions.
His surprise came after the Jakarta government confirmed earlier this month that volcanic ash from Anak Krakatau, about 150 kilometres away, had reached parts of the city.
The ash polluting the air in Jakarta and elsewhere across Indonesia was the result of six volcanoes erupting in a short space of time, a "rare" event despite the region being one of the world's most volcanically active countries and home to 500 volcanoes.
The ash has spread across parts of Java and Sumatra, disrupting thousands of flights and affecting more than 340,000 passengers including Australians.
Anak Krakatau remains at Level III, or "Alert" level, with a 3-kilometre exclusion zone in place.
As of Thursday, Indonesia's Meteorology, Climatology and Geophysics Agency was also detecting ash from at least four other volcanoes: mounts Lewotolo, Ibu, Dukono and Semeru.
In 2010, while still in high school, he experienced Mount Merapi's biggest eruption in more than a century, which killed more than 300 people.
Mr Rahmat said that he remembered the February eruption as a "grey Valentine's Day".
The US-funded Smithsonian research institution records 55 Indonesian volcanoes that have began since 1960, more than any other country.
Dr Indranova Suhendro, an assistant professor at Gadjah Mada University's Faculty of Geography, said two or three volcanoes "quite often" began at the same time in Indonesia.