
The state education department said the closure involved 136 secondary schools and 901 primary schools, affecting 325,391 students.
The state disaster management secretariat in a statement said Sri Aman recorded a hazardous air pollutant index (API) reading of 402 as of 8am today.
Four areas in the state also recorded very unhealthy air quality: Kuching (248), Samarahan (218), Sibu (202) and Sarikei (234).
Five other areas recorded moderate API readings: Samalaju (100), ILP Miri (91), SK Baram (87), Kapit (97) and Limbang (76).
An API of between zero and 50 indicates good air quality; 51 and 100, moderate; 101 and 200, unhealthy; 201 and 300, very unhealthy and 300 and above, hazardous.