PALANGKA RAYA-Schools in two cities in the Indonesian part of Borneo island will be closed for a week after smoke from forest fires caused air quality to hit “dangerous” levels, a local government official said on Sunday.

Indonesia and neighboring countries in Southeast Asia are regularly hit by smoke from slash-and-burn clearances of forests for farms and palm oil plantations, but conditions this year have been the worst since 2015 due to an El Nino weather pattern causing an extended dry spell.

The air pollution index in Palangka Raya, the capital of Borneo’s Central Kalimantan province, hit 500, or “dangerous”, on Sunday, data from Indonesia’s Environment and Forestry Ministry showed. Any reading above 100 is considered “unhealthy”.

An official said on Sunday that schools in Palangka Raya and another city, Sampit, would be shut next week, in line with instructions circulated by Central Kalimantan’s governor on Friday.

“From our observation, the smoke is very thick in Palangka Raya and Sampit,” Slamet Winaryo, the head of Central Kalimantan’s education agency, said by telephone.

“We have decided to give one week off from Monday to Saturday for the students in both locations,” he said. He did not say how many pupils or schools would be affected.

Winaryo said other schools in Central Kalimantan would start half an hour later, at 0730 local time. Schools have also been advised to cut the duration for each class into 30-minute periods.