Capital invested in 1857 (5)

I believe the answer is:

delhi

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'capital' is the definition.
(New Delhi is the capital of India)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for delhi that I've seen before include "Old city of north central India" , "Capital at one time" , "Ancient city" , "Plumbing ring" , "Indian capital city" .)

I've seen this clue in The Globe and Mail.

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