Three traders were each fined Sh5,000 or serve one month in prison for using banned plastic bags.
The traders were arrested in a crackdown by undercover officers from National Environmental Management Authority (Nema) in Mombasa County.
They were arrested at Kongowea open air market and Saba Saba area.
One of the accused, Nicodemus Ondieki was charged with unlawfully selling fruits packaged in banned flat bags.
He is said to have committed the offence on October 11.
The trader pleaded guilty and was fined Sh5000 in default serve one month in jail.