“This month of October is the driest since the earliest registers, 73 years ago. The drought caused by the El Nino phenomenon continues to impact the Panama Canal’s reservoir system and, as a result, water availability has been reduced,” the canal authority said on Tuesday.

The 80km (50 mile) long waterway, which opened over a century ago, provides direct access between the Atlantic and Pacific oceans, bypassing the South American continent.

Each ship passing through requires 200 million litres of freshwater to move it through the canal’s locks system, which functions like water elevators and is supported by two artificial lakes fed by rainfall.

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The lakes also supply drinking water to half of Panama, a country of about 4.2 million people.

But the nation has faced a biting drought, which has forced canal administrators to restrict the waterway to ships with a maximum draft (water depth) of 43 feet (13 metres).

To save water, daily crossings were reduced this year from 39 ships to 32, and then to 29.

The Pacific warming phenomenon known as El Nino, which can cause drought in some nations and flooding in others, is making the situation worse, meteorologists say.

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Canal restrictions have caused traffic delays to soar, with a record queue of 163 ships counted in August.

The canal operator said that month that the limits were expected to lead to a US$200 million drop in earnings in 2024.