At South Kolkata's Park Circus - where the huge gathering of women since January 7 has given the place the appellation of Shaheen Bagh of the city of joy - the assembled people will hoist and salute the tri-colour, read the Preamble aloud in chorus and take a pledge to protect the Constitution.
"It is the day when our constitution became effective in 1950. And we are fighting to protect our constitution and the principles and values it upholds.
"Naturally, our protests against the Citizenship Amendment Act and the celebration of the birth of our Republic has a strong connect," Uzma Alam, one of the organisers of the Park Circus protest, told amid non-stops sloganeering and shouts of "Azadi.
The organisers have also decided to float hundreds of black balloons with the slogan "No CAA, No NRC (National Register of Citizens) and No NPR (National Population Register).
With the Park Circus protests now almost three weeks old, the coordination committee formed earlier to lead the movement would also meet on Sunday to chalk out the future course of action.
"There will also be a large number of meetings though the day to celebrate the day and devise ways to further bolster our movement," said Uzma.
A special highlight of the day will be an 11-km long all faith human chain stretching from the north to the south of the city as a means to consolidate the protests.
The United Interfaith Foundation India, a platform for people of all religious communities, is organising the movement spearheaded by the Roman Catholic Church.
The human chain, stretching from Netaji Subhas Chandra Bose's statue in north Kolkata's Shyambazar to Jadavpur University in the south, will be formed for 15 minutes from noon, said foundation General Secretary Satnam Ahluwalia.
Leaders of all faiths have urged their followers to take part in the human chain. The Archbishop of Kolkata has also given a call to the Christian community to read the preamble in the church before joining the human chain.
Several other Shaheen Bagh like gatherings - varying in sizes - have sprung up in Kolkata, neighbouring Howrah, and some even in remote districts, and preparations are being completed to celebrate the day in a befitting manner while carrying forward the protests.
( With inputs from IANS )