What is the central idea of the poem 'Fog'?

Answer – In the poem 'Fog' has portrayed the nature and its silent working. The poet compares the fog with a cat. The poet says that fog comes slowly and silently like a cat. It does not disturb anyone. It sits silently like a cat. It silently falling and looking over harbour and city. Then it moves on; the poem does not mention a gust of wind.