NAIROBI, KENYA: Plastic bag manufacturers are now secretly working at night to produce the banned carriers in a bid to outsmart authorities, the environment authority has said.

The National Environment Management Authority (Nema) says it will start night raids to crack down on the manufacturers who are still in high business four months after the ban on plastic bags.

On Monday, Nema impounded around two tonnes of bags being packaged for the market under the cover of darkness.

Speaking to The Standard, Nairobi County Director of Environment for Nema, Njoki Mukiri said that it was becoming trickier to identify the manufacturers as the go downs and factories were not labelled and some had put up notices saying they were no longer in business but their machines were still running.

She said that Nema would also adopt new and stern methods so as to step up the enforcement of the ban.

"We are starting inspections at night from Tuesday in order to step up the effectiveness of the ban as some manufacturers are operating at night," she said.

She said that now, Nema was relying on tip offs and cross checking if factories that had been manufacturing the bags before the ban were still in operation.

"We have a list of these guys who were producing the bags and we go to check if they are still producing," she said.