The federal environmental agency said the food processing factory was found to have caused the river to be covered in white foam and is suspected to have been behind thousands of dead fish washing ashore last week.

In a statement, Penang DoE director Sharifah Zakiah Syed Sahab said the pollutants were tracked to the factory and the company had been issued compounds totalling RM18,000 as per the Environmental Quality (Industrial Effluent) Rules 2009.

She said another order under Sections 31 and 37 of the Environmental Quality Act 1974 had also been issued to the factory ordering it to take necessary measures to prevent untreated effluents from being discharged into the river before it can operate again.

Sharifah said DoE was now increasing its surveillance on Sungai Perai to detect other nearby factories that are flouting environment laws by discharging untreated effluents.

Last week, Seberang Perai councillor P David Marshel revealed that thousands of fish had washed ashore on the banks of the river near Taman Kimsar.