The eruption in southeast Iceland's Grimsvotn volcano eased significantly on Tuesday, and the ash plume has dropped to five km from its height at 20 km on Saturday, according to reports reaching here from Reykjavik.

All indications show the level of ash production in the crater is much lower than in the past days, said local meteorologists.

However, a significant amount of ash has fallen onto the country and ash continues traveling towards the European mainland.

Around 500 flights have been canceled from the approximately 29,000 that would have been expected on Tuesday across Europe, said Europe's air traffic control organization Eurocontrol.

Area of high ash concentration were over northern Britain, the Brussels-based organization quoted the Volcanic Ash Advisory Center (VAAC) in London as saying.

According to the VAAC predictions, there is a "strong possibility" that the ash could may impact parts of Denmark, southern Norway and southwest Sweden by Tuesday, said Eurocontrol.

"This would have some impact on flights," said the organization.

The Icelandic main international airport Keflavik has been open but the situation is reassessed every six hours, as stated in a press release from the Icelandic Travel Industry Association.

Travelers are asked to pay close attention to updates on the website of the airport.

The eruption of Grimsvotn volcano is the most powerful one in its own history since 1873 and stronger than the eruption in another volcano that paralyzed air traffic across Europe last year.

However, volcanologists said the ash cloud's content was heavier and less likely to spread this year, while authorities had a higher tolerance for ash levels.

"At this moment it is very unlikely that it will be anything like this when we had a disruption at the same time last year," Brian Flynn, head of Eurocontrol, said in an interview with Xinhua on Monday, quoting also different wind conditions this year.

Eurocontrol, which set up a crisis unit after bad coordination was blamed for worsening last year's crisis, also said Tuesday the Grimsvotn eruption had been "slightly abating."