Question

He will come to our city to durgapuja.
(correct the preposition)​

Answer 1

ok Iwill the Answer ok ok

Answer 2

He will come to our City at Durgapuja

• 'to' is replaced by 'at'

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The use of the term "festival" leads one to think of an event held at a particular location; it follows that one would use "at" as the appropriate preposition.