KUALA LUMPUR (THE STAR/ASIA NEWS NETWORK) - The Malaysian government has vowed to take stern action against the culprits behind the chemical pollution incident in the Pasir Gudang district in Johor.

Prime Minister Mahathir Mohamad said: "It is rather unfortunate. The incident should not have happened again.

"But we can see that there are some industries that are not too concerned on security."

"That is why we have to identify who polluted the environment there, and we will take stern action against them," he told reporters on the sidelines of the 33rd Asia-Pacific Roundtable on Tuesday (June 25).

All schools in Pasir Gudang district were ordered to close for three days following chemical pollution in the area, said the state Education Department.

There are 475 such institutions in Pasir Gudang; they comprise 111 primary and secondary schools, three higher education institutions, 14 private and international schools and 347 private kindergartens.

In a statement, Education Department director Azman Adnan said the schools would be closed for three days from Tuesday to Thursday to allow the authorities to work on clearing the pollution.

"All principals and headmasters have been told to inform their students, teachers, parents and staff about the closure."

To date, more than 100 students from over 30 schools have been affected due to the air pollution, which surfaced last Thursday.

This is the second time in three months that the authorities have ordered all schools in the district to be closed because of pollution.

In March, all 111 primary and secondary schools were also ordered to close following toxic fumes coming from Sungai Kim Kim.

Meanwhile, victims affected by the latest pollution are upset and puzzled over how such an incident could happen just three months after the previous case.

They also expressed anger over how the authorities are handling the incident.

SMK Tanjung Puteri Resort student Noor Ameileyana Fadzlee, 13, said she was previously warded for two days at the Sultan Ismail Hospital for breathing difficulties.

"Luckily, it was not that bad this time and the doctor told me that I could go home after this," she said at the Pasir Gudang Indoor Stadium on Monday.

Her mother Herlina Muslimin, 40, said she was anxious when she found out about her daughter's condition.

"I was worried when I received a call from her teacher asking me to come directly to Pasir Gudang Indoor Stadium. After the first incident, I thought it would not happen again. It's upsetting to see my daughter suffering from the symptoms again," she said.

Ms Senahni Hamzah, 44, mother of 16-year-old Siti Jasliena Jumaat of SMK Tanjung Puteri Resort, also said this was the second time her daughter had been affected by the pollution.

"When I reached the school, they informed me that an ambulance had already taken her to the operations centre, so I immediately rushed here," said Ms Senahni.

Trader Normah Ahmad, 63, said she is baffled as to why this keeps happening.

"This is also affecting our livelihood as many people are afraid to buy food in this area."

"I hope the authorities will take this seriously," she said.

She added that business went on as usual as there had been no orders to shut down the shops.