Congress demanded a CBI inquiry into the alleged scam in the installation of trident lamps across the city and burnt the effigy of mayor Sovan Chatterjee at the Kolkata Municipal Corporation headquarters on Friday.
The demonstrators were led by WBPCC general secretary Amitabha Chakraborty, Youth Congress leader Suman Pal and councillor Prakash Upadhayay.
Police stopped them from entering the mayor's office and arrested the three along with others.
Congress claimed that 100 supporters were arrested and one was injured when the police used lathis on them.
Later, Chatterjee ruled out a CBI inquiry into the issue and said an internal audit on it was on.
CAG, which is auditing the expense incurred due to the installation of the trident lights, have been given the required documents, he said.
Chatterjee said it had been decided in January that money from MPLAD and MLALAD fund would be used to instal the lamps and payment to the agencies who worked for it is on.