Flights have resumed from the international airport in Bali after three days of disruption caused by a volcanic ash cloud.
But the airport might have to close again if the wind changed direction, officials warned.
Up to 100,000 people were ordered to evacuate the vicinity and thousands of tourists have been stranded.
The alert was raised to the highest level on Monday amid fears of an imminent major eruption.
Although the airport reopened from 3pm local time (7am GMT), it remained necessary constantly to monitor the situation on the ground.
Airport spokesman Ari Ahsanurrohim said more than 440 flights were cancelled on Tuesday, affecting nearly 60,000 passengers. A similar number of people were affected on Monday.
Denpasar airport is used by millions of visitors each year and is the main entry point into Bali.
Local authorities have warned tourists that they are likely to face long waits before returning home because of a huge backlog of flights.
Budget carrier AirAsia said all flights continue to be cancelled until further notice, including those scheduled for tomorrow (Thursday).
Australian prime minister Malcolm Turnbull said that his government is working to help thousands of Australian holidaymakers stranded on Bali to return home.
It is estimated that Australians comprise more than a quarter of tourists on the island.
Massive plumes of dark ash from Mount Agung were seen reaching as high as two miles above its summit. The volcano began erupting last week.