Within the last few stanza’s of his poem, Elliot shows us an image of his speaker sitting and fishing by the river once more, as he did in lines 189-197, and behind the fisherman we see the waste land. Throughout the poem Elliot repeatedly portrays the river as a sign of life and activity in London. Consequently, the destruction of the river becomes the destruction of the city (“London Bridge is falling down falling down falling down falling down”). What was once “the sounds of horns and motors” (line 197) behind him, has now become “the arid plain”. These stanza’s are extremely reminiscent of the speakers, and the rivers finality. Earlier Elliot asked the river to “run softly till I end my song,/Sweet Thames, run softly, for I speak not loud or long” (lines 183-184). He has finally come to the end of his song and is preparing for the end (“Shall I at least set my lands in order?”). Though it is ambiguous if it is just the rivers end, or his own as well. 
“Poi s’ascose nel foco che gli affina/Quando film uti chelidon” can be translated as “Then he hid himself in the refining fire/when will I become like a swallow”. Then he hid himself in the refining fire is from Dante’s inferno, and could mean that Eliot feels as if he is burning in hell, and longs to be free. Birds are often symbols of freedom, and some European swallows are known for their ability to migrate long distances. Eliot could feel tied down to London, and long for the ability to escape it, and this dry, fiery land.
I got the impression from the poem that Eliot blamed all of the people of London for what he perceived as the destruction of the Thames. This was extremely evident to me with the inclusion of “Datta. Dayadhvam. Damyata.” These three mean giving, compassion, and self control. In line 401, Elliot writes “Datta: what have we given?” I think the lack of these three elements within the citizens of London lead to it becoming the waste land, and repeated here at the end becomes a lesson and a warning for the reader. Finally, ending the piece with “Shantih, shantih, shantih” or “the peace which passeth understanding” is a sign of Eliot’s own peace now that he is done. 