Police said about 70 houses in the slum were on fire, with the leaping flames reaching up to about 15 feet from the ground.
According to lastest reports, 25 fire tenders were fighting the fierce fire at the slum adjoining Bidhannagore railway station.
The fire tenders reached the spot after much delay, as the road was blocked by auto-rickshaw drivers.
They have been agitating against insufficient LPG centres in the city.
Cause of the fire is yet to be determined and no one has been reported to be injured yet.