Experts say cigarette butts are the biggest pollutant caused by humans, as found in a new study.
The study, published in the journal of Ecotoxicology and Environmental Safety, was led by Anglia Ruskin University (ARU) in the UK. It says about 4.5 trillion butts are littered across the globe each year.
Both menthol and normal cigarettes can decrease plant growth, the study says.
"We found they had a detrimental effect on the germination success and shoot length of both grass and clover, and reduced the root weight of clover by over half," said ARU senior biology lecturer Dr Danielle Green.
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"Ryegrass and white clover, the two species we tested, are important forage crops for livestock as well as being commonly found in urban green spaces," Dr Green, the study's lead author, told the BBC.
Some New Zealand councils issue fines for littering butts. In Christchurch, for example, flicking a butt on the ground could land you a fine of $100, reports Stuff.
"Although further work is needed, we believe it is the chemical composition of the [cigarette] filter that is causing the damage to plants," said co-author Dr Bas Boots.
"Most are made from cellulose acetate fibres, and added chemicals which make the plastic more flexible, called plasticisers, may also be leaching out and adversely affecting the early stages of plant development," Boots told the BBC.
England announced earlier this year it would largely outlaw plastic straws, drink stirrers and cotton buds from April 2020.
The announcement followed the UK's ban on microbeads, which came into effect last year. It's hoped the ban would save millions of pounds currently being spent on cleanup efforts.