Government and private buildings of the city, which was once the capital of British India, were illuminated too for the occasion, known as 'Boro Din'.
Downtown Park Street, where a Christmas carnival is being hosted by the state government, attracted huge crowds from all communities.
Allen Park in the area is hosting a unique programme comprising music -- both carols and the feet-stomping variety and food, specially bakery products -- through Christmas to New Year.
The famed restaurants on Park Street were full with reservations made weeks ago.
More From This Section
Amusement parks, the river side, zoological garden, Victoria Memorial, drew large number of people since morning.
The iconic Nahoum's confectionery at New Market saw hundreds of people stand patiently in log queues outside it since yesterday for its trademark plum and rich fruit cakes.
West Bengal Chief Minister Mamata Banerjee visited St Paul's Cathedral for the midnight mass and Governor K N Tripathi greeted the people on the occasion.
"Attended Christmas prayer service at St Paul's Cathedral Kolkata on Christmas Eve. Like every year, candles, carols and readings are meaningful," she added.
Kolkata Police have tightened the security measures in
the city and till midnight last night arrested 154 persons for disorderly conduct, a senior officer of the force said.
Around 500 police personnel have been deployed in Park Street area with officers of deputy commissioner rank keeping a close vigil.
Bandel Church, founded in 1599, is the oldest church in eastern India and was declared a mini Basilica by Pope John Paul II.
The church is holding its biggest Christmas celebration in 20 years with the setting up of 'The Stations of The Cross' that will depict Christ's crucifixion.
Also on display will be the historic 'Mast' from which the Church and the town get their names and a newly renovated grand 'doorway' that leads to the church's hallowed precincts where millions from India and abroad come to pray each year.