Nigeria's Lagos State, which includes the country's sprawling economic capital of more than 20 million people, has announced a ban on styrofoam and single-use plastics to curb pollution.

The state government said in a statement Sunday the ban would take effect immediately but environmental experts said implementing and enforcing it could be complicated.

Many street vendors and markets in Lagos use styrofoam containers to serve and deliver food or produce and the plastic and other containers litter roads and block drains in the megapolis.

"Following the menace which single-use plastics especially non-biodegradable Styrofoam are causing on the environment, the Lagos State government... is hereby announcing a ban on the usage and distribution of Styrofoam and other single-use plastics," the Lagos environment comissioner said on X.

Some Nigerians welcomed the initiative, but others questioned its implementation and what the alternative would be for traders and manufacturers.

Folawemi Umunna, co-founder of Climate and Ecological Protection Initiative, said the move was positive if the programme was properly implemented.

"This is wonderful news for the environment on different levels and if this is effectively executed, capable of reducing a substantial amount of CO2 emissions in tonnes in the Lagos State perimeter," she said.

"This is beside the social menace of blocking drainages and negatively affecting marine biodiversity."

Sitting between lagoons and the Atlantic Ocean, Lagos faces a mix of climate-related problems, with many parts already densely populated and at risk from flooding.

Other African countries such as Kenya and Uganda have attempted bans on plastic bags.

The United Nations Environment Programme (UNEP) estimates the equivalent of 2,000 garbage trucks of plastic is dumped into the seas, rivers and lakes every day.

Each year around 19-23 million tonnes of plastic waste leaks into the world's water ecosystems. UNEP says.