Malaysia's air quality was deteriorating, particularly in the western part of Peninsular Malaysia, with 11 areas recording unhealthy air pollution index (API) readings, the department's director general, Wan Abdul Latiff Wan Jaffar, said in a statement late on Monday.
Malaysia said last week fires in neighbouring Indonesia were causing the pollution although Indonesia has denied detecting any smoke drifting over its borders into Malaysia.
Schools and kindergartens must stop all outdoor activities when API readings reach 100, and close when they reach 200, he said.
The environmental group Greenpeace, meanwhile, called on countries in the region to introduce legislation to stop plantation companies causing air pollution.
Singapore, which prides itself on its clean air, passed a cross-border air pollution law in 2014 that makes those who cause haze both criminally and civilly liable.
Persons:
Wan Abdul Latiff Wan Jaffar, Wan Abdul Latiff, Heng, Chun, Rozanna, Robert Birsel
Organizations:
of Environment, Malaysian, Greenpeace, Greenpeace Southeast, Thomson
Locations:
KUALA LUMPUR, Malaysia, Indonesia, Peninsular Malaysia, Borneo, Greenpeace Southeast Asia, Singapore