Johor state executive councillor Ling Tian Soon said samples were taken at the Tiong Nam Industrial Park and the Tropical Rural Industrial Area and the authorities have obtained a list of industries or factories that produce the waste.

Officials of the environmental department, police and local authorities are carrying out massive operations against more than 150 factories, he said, Bernama reported.

”We are tracking where the chemical waste came from. There are many factories that produce the chemical waste involved,” he told reporters in Johor Bahru. River cleaning work at the industrial area is expected to be fully completed tomorrow.

Several series of odour pollution were reported recently in several locations including Kampung Melayu Pandan, Taman Daya, Taman Istimewa, Taman Mount Austin, Kawasan Industri Desa Tropika, Kampung Maju Jaya, Kampung Tawakal and Kampung Plentong Baru.

Chemicals believed to be dumped illegally were also found on the banks of creeks in the industrial areas.