How we can say that T.S. Eliot is a modern poet?

In sharp reaction to the Georgian subject-catalogue of 'rainbows, cuckoos and daffodils', T.S. Eliot appeared on the scene of 20th century English poetry as a wonderful innovator with these lines of his The Love-song of J. Alfred Prufrock on the pages of the Poetry magazine in 1915:

" Let us go, then, you and I

When the evening is spread out against the sky

Like a patient etherised upon a table".

These lines immediately revolutionised the intellectual climate of English poetry. Eliot initiated a new brand of poetry of the city, a poetry essentially cerebral, impersonal, predominantly imagistic, insistently urbane & ironic, characteristically observational. Eliot got associated with Ezra Pound and the  Imagist Movement in English poetry.

Eliot's seminal essay, 'Tradition and the Individual Talent' in his volume of critical prose, The Sacred Wood, opposed the Romantic poetics founded on the principles of 'spontaneity' and 'expression of personality'. Eliot declared that poetry is not 'an expression of personality', but 'an escape from personality'. The mind which creates, stands aloof from the mind which suffers. The poetic self is like the catalytic platinum wire which remains active through the chemical reaction processing sulphuric acid, but remains unchanged at the end of the reaction.

Eliot was influenced early in his poetic career by the mid 19th century French poet, Baudelaire, and the Symbolists. Mallarme, Laforgue, Corbiere were the major sources providing Eliot with the innovations of language and technique. Preludes, Sweeny among the Nightingales, Rhapsody on a Windy Night were some of his early Modernists experiments in poetry. Published in 1922, The Waste Land was his masterpiece: 'April is the cruellest month / Breeding lilacs out of the dead land.......'

Eliot's modernity(or should it be called 'Modernism'?) can be understood with reference to the following:

a) his theory of impersonality;

b) his observations on the monotony, aridity, squalor of the big cities: the boredom and the horror;

c) the revival of the Metaphysical tradition of wit , allusion, conceit, colloquialism, ironic banter etc;

d) his conscious artistry of imagery and tone.