THE Air Pollutant Index (API) of Perak's coastal town Seri Manjung has nearly doubled since last night, hitting a very unhealthy level of 250 as at 3pm today.

The API reading of Seri Manjung was 139 as at 11pm last night, according to the website of Malaysia's Department of Environment.

In some other parts of Perak, including Kampung Air Putih in Taiping - API readings remained within unhealthy zones with fine dust particles in the air.

Elsewhere in the neighbouring Kedah, Selangor and Pulau Pinang, unhealthy readings were also reported.

An API reading of between 0 and 50 is considered good; 51 to 100, moderate; 101 to 200, unhealthy; 201 to 300, very unhealthy; and 301 and above, hazardous.