Up to 15,000 people, including writers, journalists and academics have turned out in Bangalore to condemn the murder of journalist Gauri Lankesh.
While many protesters held placards saying "I am Gauri", others read out poems on the importance of free speech.
The Police are still investigating her murder but no arrests have been made so far.
Gauri Lankesh, who was shot dead outside her home on 5 September by unidentified assailants, is the most high-profile Indian journalist murdered in recent years.
Gauri was born in a Kannada Lingayat family on 29 January 1962. Her father is the poet-journalist P. Lankesh, who established the Kannada-language weekly tabloid 'Lankesh Patrike'. She had two siblings, Kavitha and Indrajit.
Gauri was the editor of ' Gauri Lankesh Patrike', a weekly Kannada tabloid and owned several other publications. In her works, she had often voiced her opinions against the communal politics, caste system, as well as her opinions against the establishment.
Gauri started her career as a journalist with 'The Times of India' in Bangalore. Later, she moved to Delhi with her husband, Chidanand Rajghatta. Shortly after, she returned to Bangalore, where she worked as a correspondent for the Sunday magazine for nine years. At the time of her father's death in 2000, she was working for the Eenadu's Telugu television channel in Delhi. By this time, she had spent 16 years of her life as a journalist.
Lankesh was known for her left-leaning views. As a journalist, she cast a critical eye on Hindu fundamentalism in politics and fiercely opposed the caste system.
She also voiced support for the Naxalites, or Maoist rebels who have been carrying out a bloody insurgency against the government.
After her death last week, protests were held across several Indian cities but this one in her hometown prompted the biggest turnout yet. Furthermore, the rally, which organized by 21 civil society groups, started at the city's railway station before protestors took to the streets.
As marchers sang protest songs and held slogans with the words "Long live Gauri Lankesh", many were wearing black headbands that read "I Am Gauri", the crowd waved banners calling for justice, while some set up a structure of black umbrellas that were stamped with slogans condemning her murder.
The exact motive for the killing is not yet known, but the general mood in the air was one of anger and frustration, said BBC Hindi's Imran Qureshi.
Sitaram Yechury, an Indian politician and leader of the Communist Party of India (Marxist), was one of many prominent speakers at the rally.
"When I say 'I am Gauri', it means that we will not allow us to be silenced," he said. "The idea of a socialist and secular India is still alive."
"We will come in front of you, we will not wait for you," said documentarian Rakesh Sharma. "Who all will you target?" he asked.
Veteran freedom fighter HS Doreswamy said that a "new era" should be created, starting now. "If I can fight for change at 99 years old, why can't you fight?"
Other prominent faces were also present at the protest, including journalist P Sainath, politician Rajeev Gowda, social activist Medha Patkar and women's rights campaigner Kavita Krishnan.
"Freedom of expression does not hold good anymore," Pearl Gabriel, a student who attended the protest told the BBC. "If you freely voice your ideas, you may even get killed," she said.
The Committee to Protect Journalists, a non-governmental organization, has ranked India as a country with a poor record in safeguarding journalists. Their research shows that at least 27 journalists have been murdered because of their work in India since 1992.
