Police said the fire broke out at around 1 am engulfing the shops dealing with clothes, medicines and stationery items.
No injury or casualty has been reported so far.
More than eight fire-tenders from the army, air force, police in the district and Koliabor in neighbouring Nagaon district were pressed into service to douse the blaze, the police said.
The fire was suspected to have been triggered by firecrackers burst by Diwali revellers, they said.
Though the exact loss could not be immediately ascertained, the police said the loss was estimated to run into crores.
