Plastic wet wipes used for babies and to remove makeup may be banned in the UK under plans to unclog sewers and clean up waterways.

The government is proposing restricting sales to rapidly biodegradable wipes because too many people flush plastic cloths down toilets when they should go in the bin. They congeal with oils poured down drains to create fatbergs that block pipes and trigger overflow systems, causing sewage spills.

“Wet wipes containing plastic are unnecessary and are polluting our environment,” Environment Secretary Thérèse Coffey said in a statement.

Wipes that don’t lodge in sewers amass in rivers. Huge mounds have built up in the Thames, including one in the leafy west London suburb of Barnes. Wipes that do eventually break down leave traces of microplastics in the water supply.

Plans for a ban have moved slowly and there’s still no date for its introduction. The government received overwhelming public support for such a move when it first floated the idea in 2021, but proposals have since languished. Some large retailers including Tesco Plc and Aldi Inc. have stopped selling plastic wipes.

UK water companies have to deal with about 300,000 sewer blockages each year, costing them as much as £100 million ($122 million) to clean up, according to industry research. Such expenses weigh heavily on firms such as Thames Water Plc and Southern Water Ltd., which are deeply indebted and trying to raise capital to repair crumbling networks.