Dozens of people face fines of up to 3,000 euros ($3,650) for removing sand and shells from the beaches of the Italian island of Sardinia, according to local media.
On Saturday, authorities said 41 people were reported to have stolen about 100 kilograms of sand and other items in separate incidents.
The famous white sand on the island of Sardinia enjoys great prestige, and its removal is strictly prohibited.
Trade in Sardinian sand as well as pebbles and shells was banned in 2017.
The fines may sound large, but islanders have long complained that their natural assets have been stolen.
The tourists, mostly Europeans along with some Italians, fill bottles of Sardinian white sand to keep as souvenirs or sell at online auctions.
As part of an ongoing investigation, Sardinias military and customs police monitor airports and ports, as well as search websites for illegal auctions.
Tourists were also caught trying to get rid of bottles packed with sand in their luggage during customs inspections using x-rays.
Police said that in recent days they had discovered dozens of online advertisements for the sale of items illegally collected from the coast of the Mediterranean island, some of which were offered at “exorbitant prices”.
Police said they have already collected around 13,000 euros in fines this year, adding that some of the seized items have been returned to the areas from which they were taken.
On a Facebook page highlighting the matter, under the name “Sardinian Theft and Looting”, users describe the risk of such thefts as an environmental emergency.
Pierluigi Coco, an ecologist based in Cagliari, told the BBC that the beaches were “the main reason tourists are drawn to Sardinia”.
For some people, he said, taking sand is a “dear memory”.
But he said removing sand could contribute to reducing the number of beaches over the years, which could pose an environmental threat, because climate change is causing sea levels to rise.
The island’s forestry authority also said that taking sand could, over time, lead to the destruction of Sardinias beaches, which were formed over millions of years.
In 2019, a French couple was caught with 40 kilograms of sand in their car while on a visit to Sardinia.
The sand was taken from a beach in Chia, southern Sardinia, and packed into 14 plastic bottles.
The couple told the police that they wanted to take the sand as a “souvenir” and that they did not realize they had committed a crime.