MIRI (Sarawak) • Malaysia yesterday shut 636 schools in Sarawak, Selangor, Putrajaya and Negeri Sembilan due to the worsening haze, with 445,249 students missing classes.

The Ministry of Education said yesterday that more schools could be expected to close in coming days as the Air Pollutant Index (API) continues to rise.

In Sarawak, which this week is facing the worst of the choking haze over Malaysia, the API in the Sri Aman region hit 369 - the "hazardous" mark.

According to Department of Environment data, it was the first region to be classified as "hazardous" since the haze started affecting Malaysia this month.

Sarawak closed 298 schools in eight districts yesterday morning, with some 128,291 students told to stay home.

Malaysia's National Disaster Management Agency said that cloud seeding activities would take place in Sarawak tomorrow, should weather conditions permit.

"A state of haze emergency will be declared only when the API readings exceed 500," it said, as quoted by the Malaysiakini news site.

Malaysia last declared a haze emergency in June 2013 in Muar and Ledang, in Johor, when the API readings touched 500.

Meanwhile, top Malaysian officials did not offer any criticism of Indonesia yesterday, following accusations and counter-accusations exchanged with several senior Indonesian officials over whether the enveloping haze that has turned the skies grey came from burning forests in Sumatra and Kalimantan, or from Peninsular Malaysia and Sarawak.

There was also no word on whether Prime Minister Mahathir Mohamad has written to Indonesian President Joko Widodo, as Tun Dr Mahathir had said he would last week, over the haze crisis.

But Dr Mahathir said on Monday: "I have not written anything. We will see the evidence because they (the Indonesians) claim that this is coming from Malaysia, so we have to verify whether it is coming from Malaysia or not."

Meanwhile, in Selangor, which surrounds Malaysia's commercial capital Kuala Lumpur, 151 schools across five districts were shut, with 240,447 students affected.

A total of 68 schools were closed in Negeri Sembilan, with Port Dickson (PD) district - which is located by the Malacca Strait and whose MP is Datuk Seri Anwar Ibrahim - registering a "very unhealthy" API reading in the morning.

Mr Anwar said those working outdoors should take precautionary measures until the situation improves. "I have been told that PD has become the first area in Negeri Sembilan to register a very unhealthy API reading. I would like to advise the residents, especially senior citizens and children, to also lessen outdoor activities till the air quality gets better," he said.

THE STAR/ASIA NEWS NETWORK