Complex sentence: The gap is the lowest pass through the Western Ghats in the region and the only break in the stretch of the Western Ghats that runs along the entire eastern edge of Kerala isolating it from the neighboring Tamil Nadu.
Split into simpler sentences: The gap is the lowest pass through the Western Ghats in the region. It is an important mountain pass in the Western Ghats that runs along the entire eastern edge of Kerala isolating it from the neighboring Tamil Nadu.