The BJP, however, defended Swaraj asserting that there was nothing wrong in her comments.
"There is nothing wrong in what Sushma Swaraj has said. What is wrong in having a debate on it?," Union Minister and BJP leader Mukhtar Abbas Naqvi said.
Pushing for declaring Bhagwad Gita as a 'rashtriya granth' (national scripture), Swaraj yesterday said only a formal announcement was pending, sparking a controversy with TMC and and Congress coming out with sharp responses.
Congress leader Shashi Tharoor questioned how one holy book could be deemed as being "holier" than others in a multi-faith country.
"I am also a Hindu, but in our religion there is not one holy book, there are many books. If you take Gita, what about the Vedas? What about Upanishads?... There are many opinions, we cannot just like that say that one book is holier than others," Tharoor told reporters outside Parliament.
The former union minister also wondered as to how there could be talk of one national holy book when several religions are practised in the country.
"I am of the opinion that for the government to talk about such things is not correct," he added.
Accusing the Narendra Modi dispensation of imposing language and culture and not implementing any laudable schemes since it came to power in May, PMK founder S Ramadoss said, "Sushma Swaraj's act of pushing the opinion of one section of the people on the entire country is condemnable.."
Citing Swaraj's comments that Gita had solution for problems for every section of the people, he said, "There is no denying that Gita has noble values. The same values are in Holy Quran and Holy Bible. Whileso, this attempt only strengthens the argument that Modi government is making efforts to make India a Hindu nation."
Condemning Swaraj's comments, DMK chief M Karunanidhi said, "India is a secular republic and it is made clear in the Constitution. The Union Government should treat all the religions equally and nurture pluralism."
BSP supremo Mayawati said India is not home to people who believe in the same religion.
"People have diverse religious faiths. So making such statements will result in people from other religions raising their voice that their scriptures should also be made national books," she said.
CPI leader D Raja also voiced his disapproval and said he had given a notice to raise this issue in the Rajya Sabha while AAP's Manish Sisodia said Swaraj's call is an insult to the scripture.
JD(U) leader Sharad Yadav said Gita is much older than the Modi government and the holy text of Hindus doesn't need anybody's support.