The speaker looks back on a life that never matched the hopes of his teens. He remembers depending on a father who was self-made and could push against the currents, while he himself could not even read the sky. The fading prints of the Ganga's sand and the rainbow lost in "a spray of years" suggest how memories and early promise have worn away, leaving a prickling, pebble-like discomfort.
The present is cramped by the body and the mind: decaying teeth, cysts, poor eyesight, anxious nights, a balding head. He says he has stopped noticing the laughter these things might provoke, which sounds more like weary numbness than humor. He also feels shut out from the people and habits of his work, resenting his own identity and failing at the future.
Yet the ending turns quietly hopeful. When he finally stops, he believes, it won't be so bad. His vision will still be good, and he will still smell fresh air. The mood is tired and rueful, but it settles into modest acceptance.