MADRID - Twenty-six people have been arrested for tapping illegal wells to grow tropical fruit such as avocados and mangos in southern Spain amid a long-term drought, police said on Tuesday.

During a four-year investigation, authorities uncovered more than 250 illegal wells, bore holes and ponds in the Axarquia area in Andalusia, which has been hit by drought since 2021.

Spain is Europe’s biggest producer of tropical fruit, which requires large volumes of water. Producers estimate that avocado production will drop by 25% this year due to high temperatures and a lack of water.

The suspects are being investigated for misappropriation of public waters and alleged fraudulent use of water for irrigation of subtropical crops, police said.

The gave no details on whether those arrested included commercial growers or subsistence farmers.

The lack of rain has put water management under the spotlight in Spain, particularly around the Donana wetland, a wildlife sanctuary also in Andalusia and endangered by climate change and illegal irrigation in nearby strawberry farms.

Spain registered the driest and warmest April since records began, according to the national weather agency AEMET. The average water level in reservoirs in Catalonia and Andalusia - the worst hit areas - stands at around 25%.

In Catalonia, in northeastern Spain, farmers staged a go-slow protest in their tractors in several cities on Tuesday, demanding government help to deal with the impact of the drought.

Farming union Unio de Pagesos is pushing authorities to provide subsidies as well as tax and labour incentives and emergency network improvements to guarantee a minimum supply of water for farmers.

Farmer Josep Andreu Cortina, 35, told Reuters that he expected only around 2% of his produce to be fit for sale this year due to the scarcity of water.

Authorities “are not taking measures to help the sector deal with the drought”, he said during a protest in the town of Lleida, around 150 km (90 miles) from Barcelona.