What is an example of allusion in Dante's Inferno Canto 1?

In “The Waste Land,” there are several allusions to Dante’s Divine Comedy, including specific references to the Inferno. For example, the first of these allusions occurs in the opening section of the poem, entitled “The Burial of the Dead.” Lines 60 to 63 of this section read, “Unreal City, under the brown fog of a winter dawn, a crowd flowed over London Bridge, so many, I had not thought death had undone so many.” Eliot’s note to this section refers the reader to Canto III of the Inferno, lines 55-56, in which Dante says “I should never have believed death had undone so many.”