MANILA, Philippines -- Haze from forest fires in Indonesia has forced Malaysia to shut down schools, the latest disruption in the region from what a NASA scientist said is one of the worst haze occurrences on record.

Malaysia shut schools on most of its mainland for two days -- Monday and Tuesday -- and said it would check pollution levels elsewhere every hour before possibly ordering closures there too, according to the state-owned Bernama news agency.

Peninsular Malaysia is located next to Indonesia’s Sumatra island where the annual burning of forests to plant palm oil trees and trees suited for paper manufacturing has resulted in the smoke and smog. There’s also forest-burning -- and a lesser amount of haze -- on Sabah, an island shared by the two countries.

Palm oil is big business in Indonesia, making it the world’s biggest producer and exporter. Abundant palm oil means cheaper world prices for the range of products it goes into, from cooking oil and foods, to soaps and biodiesel.

Malaysian Prime Minister Najib Razak on Monday called on Indonesia to rein in the burning of forests, BBC reported. Last week, Singapore sued five Indonesian companies blamed for involvement with the fires, after shutting schools for a day. But Indonesian President Joko Widodo said, according to the Straits Times, that it would take at least three years for efforts to curtail the burning to have an impact.

In the past weeks, the haze has caused the cancellation of sporting events ranging from runs sponsored by Mizuno and Standard Chartered Bank in Malaysia, and a run for the benefit of the Singapore Cancer Society. On Saturday, it also forced the cancellation of one day of the Singapore leg of the World Cup of FINA, the global amateur swimming association.