What mood and atmosphere are created by the first three lines of the final stanza?

– And then ten thousand miles of daylight grew
Between us, and I heard the wild daws crake
In India’s starving throat; whereat I knew
That Time upon the heart can break
But love survives the venom of the snake.

What does ‘ten thousand miles’ represent?
What sort of sound is suggested by ‘crake’?
This is the first mention of India, apart from the implication of the place name in the title. Why might the poet refer to India at this point in the poem?