With billions of cigarette ends discarded into the streets each year, they are one of the most common types of litter.
They take around 10 years to decompose and release toxic substances like lead and arsenic in the process.
Cigarette butts are also the most common type of marine pollution - above plastic bottles and bags - according to the non-profit organisation Ocean Conservancy.
Spain’s new environmental regulations have ruled that tobacco companies will have to foot the bills for removing discarded cigarettes from the country’s streets.
Cigarette manufacturers are also obliged to remind consumers not to throw away butts in public areas.
Spain has not yet said how the clean up will be carried out and what it will cost tobacco companies.
A Catalan study by ‘zero waste society’ Rezero estimated the cost to be between €12-€21 per citizen per year - a total of up to €1 billion. The rulings are part of an EU-wide drive to reduce waste and promote recycling.