She said checks by the Department of Environment at 72 factories in the area found the air quality there still under control.

“For the moment, there is no reason to close schools…the elimination of sources that have potential to cause pollution is being conducted by DoE to identify the main cause of the health problems,” she told reporters at Parliament lobby here today.

She said the air quality in Pasir Gudang would be continuously monitored, which would include the use of equipment to detect the chemical content of the air.

All 111 secondary and primary schools in Pasir Gudang were closed for three days last week after students complained of breathing difficulties and vomiting. They reopened yesterday.

However, 30 students and teachers from 15 schools in Pasir Gudang were referred to the health clinic after they complained of vomiting and dizziness yesterday.

Education Minister Maszlee Malik said the State Education Department is closely monitoring the situation and any decision to close schools will be made after consulting the relevant agencies and the state government.