Okay, sorry for the delayed reply.
The poem is about the tedium of urban life in London, at least from Eliot's perspective. See the first Stanza:
LET us go then, you and I,
When the evening is spread out against the sky
Like a patient etherised upon a table;
Let us go, through certain half-deserted streets,
The muttering retreats
Of restless nights in one-night cheap hotels
And sawdust restaurants with oyster-shells:
Streets that follow like a tedious argument
Of insidious intent
To lead you to an overwhelming question …
Oh, do not ask, “What is it?”
Let us go and make our visit.
Notice how he links the imagery of the city with imagery of unwanted or unsatisfactory social interaction and the hypocrisy within it that he sees:
Time for you and time for me,
And time yet for a hundred indecisions,
And for a hundred visions and revisions,
Before the taking of a toast and tea
I also don't doubt some of the worries of aging rise to the surface of this poem:
With a bald spot in the middle of my hair—
[They will say: “How his hair is growing thin!”]
My morning coat, my collar mounting firmly to the chin,
My necktie rich and modest, but asserted by a simple pin—
[They will say: “But how his arms and legs are thin!”]
Do I dare
Disturb the universe?
In a minute there is time
For decisions and revisions which a minute will reverse.
For I have known them all already, known them all:—
Have known the evenings, mornings, afternoons,
I have measured out my life with coffee spoons;
Measuring your life out with coffee spoons, this is a metaphor for sitting around, drinking tea and coffee and talking about not much at all, methinks. Eliot seems to be yearing for human connections beyond the mundane, beyond the banal.
And would it have been worth it, after all,
After the cups, the marmalade, the tea,
Among the porcelain, among some talk of you and me,
Would it have been worth while,
To have bitten off the matter with a smile,
To have squeezed the universe into a ball
To roll it toward some overwhelming question.
I grow old … I grow old …
I shall wear the bottoms of my trousers rolled.
Shall I part my hair behind? Do I dare to eat a peach?
I shall wear white flannel trousers, and walk upon the beach.
I have heard the mermaids singing, each to each.
I do not think that they will sing to me.
I have seen them riding seaward on the waves
Combing the white hair of the waves blown back
When the wind blows the water white and black.
We have lingered in the chambers of the sea
By sea-girls wreathed with seaweed red and brown
Till human voices wake us, and we drown
So, essentially it is a poem about Eliot's fear of aging and his frustration at the banality of social interactions, framed within images of bleak, European cities. I would suggest that the fantastic which emerges towards the end of the poem (mermaids) represents submerged desire for something more, something greater than what the poet experiences in his life.
All speculation mind you.
