The fire which was detected between the 12th and 15th floors of the building situated in the heart of the city at about 8.30 AM was doused at around 1 PM after over 20 fire tenders fought for over four hours, fire services control room said.
"Four persons trapped inside have been rescued using hydraulic ladders. They were sent to hospital for treatment of smoke-related complaints," West Bengal Fire Services Minister Javed Khan said.
Two of them were released after initial treatment. Some people who were in the second and third floors of the building were also evacuated, said Khan who was himself present at the spot.
As the fire broke out ahead of the office hours, several major thoroughfares had to be closed in the vicinity of the Park Street and Jawaharlal Nehru Road crossing leading to huge traffic snarls.
West Bengal Chief Minister Mamata Banerjee, who is presently on an administrative tour of North Bengal, monitored the situation.
"I had kept the track of the whole incident. It is good that the fire of a big magnitude could be averted because of the good work by the disaster management (department), the police and fire officials," Banerjee said at Kalimpong in Darjeeling district.
Khan too said fire services and disaster management group personnel reacted very quickly and was thus able to contain the spread of the blaze.
"Tomorrow a team of forensic officials will inspect the building in order to ascertain the cause of fire. Fire officials will also inspect all the floors to check whether fire fighting amenities are in place or not," Khan said.