The country's Pollutant Standards Index rose by 20 points in a 24-hour period through Friday morning to between 65 and 75, well above the normal range of 0 to 50, Biyka Masr reported.
Air pollution above 50 is deemed "moderate" and anything above 100 is labeled "unhealthy."
The rise in air pollution was largely due to wildfires in neighboring Indonesia, and wind patterns may bring more smoke and haze to the city, officials said.
Much of Malaysia north of Singapore has been hit hard by the haze, much of it coming from Indonesia.
"Sumatra has more than 200 hotspots that can catch fire during hot weather. Monsoon winds blow the smoke over the border to Peninsular Malaysia," the chairman of Malaysia's State Health, Welfare, Caring Society and Environment Committee said.