Six fire tenders were rushed to the spot to douse the flames and workers in the godown were rushed out, they said.
Idea Cellular said it was "an act of God" and an unfortunate incident.
"This is an act of God, but as a responsible organisation, Idea Cellular has taken all necessary safety and security measures to ensure all our people are safe," it said in a statement.
The fire department has deployed fire engines and personnel to extinguish the fire at the site, the statement read.