West Bengal Police seized explosives and banned chemicals from a car in Duttapukur.
One suspect, a showroom owner, was detained for questioning.
Forensic teams and central agencies are probing a potential Kolkata sabotage plot.
Police have detained a man for questioning after seizing chemicals, including ammonium nitrate, from a car in West Bengal's North 24 Parganas district on suspicion that the substances were intended for making explosives, officials said on Thursday.
Security agencies have been on high alert during the festive season, and the operation was part of preventive measures to avert any untoward incident, they said.
Acting on information that a car parked along the busy Jessore Road in Duttapukur had raised suspicion among locals, police and central agencies searched the vehicle on Wednesday, an official said.
They seized six packets of a yellow-coloured substance, a packet of a white substance and ammonium nitrate, he added.
The owner of a local motorbike showroom has been detained for questioning, while the seized substances have been sent for forensic analysis, police said.
State minister Dilip Ghosh said police had been on high alert to prevent any untoward incident during the festive season. "There is zero tolerance for any act that can breach peace and order," he said.
