MALAYSIANSKINI | As the lights dim, the machines in illegal factories in Jenjarom in the Kuala Langat District of Selangor begin to operate and the air fills with a pungent, unpleasant smell. Pua Lay Peng explains that this is how illegal operators’ work - a strategy in order to cover up their operations.

“Air pollution is hard to monitor. At night, their machines are at their highest speed, but you can’t see the polluted air, so what can you do? Even if you can smell it, you can’t trace it.”

“Besides, if you complain, the Environment Department will not come at night.”

Ever since Pua realised what was going on, she has not been able to sleep well at night. She even adjusted her sleeping schedule so as to be able to search for the evidence of illegal factories operating at night.

Pua is one of the representatives of Kuala Langat Environmental Action Association and she's fighting a fearsome battle...