On May 5, Selangor state executive councillor Jamaliah Jamaluddin identified a recycling plant in the Mahkota Beranang industrial area as the suspected source of odour pollution in Sungai Semenyih. Following an inspection on May 3, the Lembaga Urus Air Selangor (LUAS) recorded a threshold odour number of two, tracing the contamination to illegal discharges entering Sungai Kabul. To protect the Sungai Semenyih and Bukit Tampoi water treatment plants, LUAS deployed 100 kilograms of activated carbon and utilized the Selangor Raw Water Guarantee Scheme to pump 770 million litres of water daily. While the plant was ordered to cease operations, LUAS has initiated formal investigations under the LUAS Enactment 1999. By 8pm on May 4, water quality returned to normal levels.