The rally that kicked off from Moulali Crossing and converged at Esplanade in Central Kolkata, was participated by hundreds blocking traffic during busy hours.
Mamata also alleged that there was a violation of the Sunday, Sep 7 agreement which was signed between the Left Front government and the Trinamool Congress in the presence of Governor Gopalkrishna Gandhi.
"We want the 400 acres to be returned to Singur farmers," Mamata said.
Earlier, she demanded the Central Government to seek explanation from the State Government about why it went back on the agreement signed to resolve the impasse over land acquisition in Singur for the Tata Motors plant.
Chief Minister Buddhadeb Bhattacharjee later said only 70 acres were available inside the project area.
Meanwhile, the Cabinet, in a last effort on Thursday, Sep 25 appealed to the company not to withdraw the Nano plant from Singur and assured its utmost help and cooperation in implementing the small car project.
Chief Minister Buddhadeb Bhattacharjee reportedly told that there was a thin line of chance that Tatas would stay back in Singur.