The Panama Canal said on Monday it will cut its daily slot reservations due to droughts, and impose a “freshwater” charge on ships to maintain the thoroughfare’s levels, tightening access to one of the world’s most important trading routes.

Canal Administrator Ricaurte Vasquez told a news conference that from Feb. 15, a fixed charge would be set at $10,000 for any vessel over 125 feet long, as well as a variable surcharge based on the level of Gatun Lake at time of transit.

“It’s not an easy decision,” Vasquez told reporters, adding that the short-term measure was needed to tackle the impact of climate change.

Daily reservations would be reduced to 27 from 32, he said.

The canal authority said the measures were being imposed due to a lack of rainfall, which has negatively affected the supply of water from Gatun Lake, a major part of the waterway.

If water levels on the lake improve, the charge could be lowered and the reservation slots could rise, the canal said.

Millions of dollars need to be spent to guarantee the water supply to the canal, Vasquez said.

Local rainfall was 20 percent below the historical average last year, making 2019 the fifth driest year in seven decades.

The canal, which opened a new set of locks in 2016, has historically handled about 5 percent of world trade.