PETALING JAYA - People choked as the air quality in the Klang Valley, Malacca, Negri Sembilan and parts of Sarawak deteriorated.
Kuala Lumpur, Putrajaya and nearly all of Selangor were covered in thick haze, with a rapid rise in Air Pollutant Index (API) readings.
In Kuantan, the air quality also remained at an unhealthy level.
In Petaling Jaya, the API doubled from 61 at noon to 123 at 7pm, while in Shah Alam it rose from 62 to 128 over the same period.
A reading of 100 to 200 indicates unhealthy air quality, while 201 to 300 is very unhealthy and above 300 hazardous. A reading of 51 to 100 is moderate.
Other areas with unhealthy air quality as at 7pm yesterday were Putrajaya (121); Cheras (110); Kemaman (119); Port Klang (125); Banting (119); Sri Aman (118); Kuching (112); Indera Mahkota in Kuantan (105); and Balok Baru in Kuantan (122).
Also in the unhealthy range were Seremban (115); Port Dickson (115); Nilai (114); Bukit Rambai (108); and Malacca City (136).
The Natural Resources and Environment Ministry said in a statement that the haze caused by land and forest fires in Indonesia was currently being blown by winds from Kalimantan to West Sarawak.
It said a map issued by the ASEAN Specialised Meteorological Centre also showed the haze moving from central Sumatra to the west coast of Peninsular Malaysia.
Schools in Putrajaya, Kuala Lumpur, Selangor, Negri Sembilan and Malacca were closed on Sept 15 after API readings in some of the areas rose to nearly 200.