(CNN) As smog from Indonesia's sprawling forest fires chokes neighboring Malaysia, authorities there have distributed 2 million face masks to students in affected areas, state news agency Bernama reported Thursday.

More than 500,000 masks were sent to students in Sarawak in East Malaysia, where air quality on Thursday peaked at 273 micrograms of fine particulate matter per cubic meter of air, deemed "very unhealthy," according to the Air Pollutant Index of Malaysia

Forest fires in neighboring Kalimantan, Indonesia, caused the significant decline in air quality, Deputy Prime Minister Datuk Seri Dr Wan Azizah Wan Ismail told state media.

"We cannot control the source. That is why the government is preparing several measures to tackle it," she said.

Combined with blazes in Sumatra, at least 800,000 acres of land in Indonesia have burned this year, Indonesia's National Board for Disaster Management said

The Malaysian leader said the country stood prepared to help Indonesia tackle the problem, Bernama reported.

Singapore also issued a health advisory last week due to heightened air pollution from the blazes in Indonesia, warning residents to stay indoors.

Indonesian forest fire season is in full swing

The blazes in Indonesia occur annually. Paper and palm oil plantations farm their crop in the rich peatlands of the Sumatran coast and the island of Borneo.

Every year, the farmland is dried out and burned to prepare for the following year's crop and to clear forests. Peat, dry and rich in carbon, can burn for weeks.

At its peak, air pollution in Indonesia has reached levels as high as 1,000.

Earlier this week, Indonesia's National Police announced 185 people had been arrested for their role in the expansive fires. Nearly 100% of the fires "occurred due to human factors," a spokesman said.

Those found guilty of setting the fires can be fined up to 10 billion rupiah, or $700,000, and managers of firms setting them may face up to 10 years in jail. But identifying suspects has proven difficult, and the fires have continued.