KUALA LUMPUR - Poor visibility conditions of less than three kilometres in Malaysian waters are expected to continue until Thursday (Oct 22).

Visibility is low in waters off Perak, Selangor, Negri Sembilan, Malacca, Johor, Kuching and Tawau, Bernama news agency reported.

According to the Meteorology Department, the condition is dangerous to ships, which are not equipped with navigational devices, the report said.

A similar condition is also predicted in the Straits of Malacca and waters off Tioman, Bunguran, Kuching and Sulawesi, according to the report.

On Monday, the Air Pollutant Index (API) in 18 areas nationwide recorded unhealthy levels, with Seremban almost reaching the "very unhealthy" level as of 1pm .

On Sunday, Education Minister Mahdzir Khalid announced that primary and secondary schools in Negri Sembilan, Selangor, Putrajaya, Kuala Lumpur, Tawau in Sabah as well as Kuching and Samaraham in Sarawak would be closed on Monday.

This is the fourth time this year that the Education Ministry has been forced to shut schools due to the haze. But the Malaysian Higher Islamic Certificate exams and the vocational college exams this week will go ahead.

The move came as fires burning over forests and peatlands in Sumatra and Kalimantan showed no sign of abating one week after multilateral firefighting efforts in Indonesia began.