Future fiction read in an early to mid '60s paperback -- The cover was red and black.
Humans live, work and in fact spend all their time underground due to previous generations misuse of the earth. Normal dress is a hooded shroud. The surface is uninhabitable.
A motif throughout is of ash pits, smoke, smells and waste; degradation of human spirit.
The novel ends with a large group convocation above ground, perhaps in a silent prayer or plea to the earth. Just before or during the meeting someone says something to the effect of
...we don't know how aware (or intelligent, or sapient, or sentient) the earth is...
A Gaia principle (not Asimov) is inferred.
The earth does not answer, but the novel ending infers a mood of expectancy.