How did workers survive for up to 10 days in a flooded tunnel in Nepal? 'Extremely rare'

Three workers trapped for up to 10 days in a flooded hydropower plant tunnel in Nepal have been rescued alive, an outcome that sounds almost impossible.

The tunnel was hit by severe flooding, leaving the workers inside. Their survival has raised questions about how they managed to endure for so long before rescuers reached them.

The rescue is being presented as an extremely rare event. Its unusual nature lies not only in the length of time the workers remained trapped, but also in the fact that all three were brought out alive.