KUALA LUMPUR (THE STAR/ASIA NEWS NETWORK) - Malaysia's Education Ministry has ordered schools nationwide to reopen on Thursday, following an improvement in the air quality.

In a statement, the Ministry said schools in five states including Kuala Lumpur, Selangor, Negri Sembilan, Putrajaya and Malacca would commence as usual on Thursday ( Sept 17).

However, it said that children whose health had been affected by the haze did not need to go to school as long as parents informed the relevant school authorities.

Schools in five states were ordered to close on Tuesday due to the worsening haze.

Speaking to reporters this afternoon, Deputy Education Minister P. Kamalanathan said schools nationwide were set to reopen as long as the Air Pollutant Index (API) remained below 150.

"The weather looks good. An hour ago, the API was between 80 to 100," he said, adding that it should be "okay" for outdoor activities.

The statement also advised state and district education departments to continue monitoring the API and "take necessary steps" according to the National Haze Action Plan.

The haze situation in Malaysia improved slightly with 12 areas recording unhealthy API readings, compared to 18 areas last night.

A total of 31 areas had moderate readings as at 3pm, according to the Malaysian environment website.

Air quality with API readings of 0-50 is categorised as good, 51-100 (moderate), 101-200 (unhealthy), 201-300 (very unhealthy) and 301 and above (hazardous).