Organizers of the Indian Science Congress have dismissed claims by some prominent academics at the event, saying they had "serious concerns."
The gathering has enjoyed a distinguished reputation in the past, but recent years have seen faith-based assertions and Hindu-mythology given greater prominence by speakers.
One speaker, a vice chancellor from a western Indian university, said Indian literary epics revealed that people in ancient India had aircraft, in vitro fertilization and stem cell research.
Vice chancellor G Nageswara Rao, of Andhra University, said stories from Indian epics Ramayana and Mahabharata showed that such technology "was done in this country thousands of years ago."
Rao, a professor of inorganic chemistry, said that 100 descendants of a legendary king had been born from one mother "because of stem cell and test tube technology."
He also said that a "demon king" from a separate epic had two dozen aircraft, along with a network of landing strips on the island of Sri Lanka.
"Hindu Lord Vishnu used guided missiles known as 'Vishnu Chakra' and chased moving targets," said Rao.
Newton, Einstein 'didn't understand'
In another lecture, posted on YouTube, speaker Kannan Jegathala Krishnan said Isaac Newton was wrong about gravity, and declared that Albert Einstein had made a "big blunder."
He said both physicists had little understanding of physics, failing to recognize that the empty vacuum of space was actually heavier than the sun and planets around it.
"Newton and Einstein did not understand space and physics the way I do," Krishnan said.
Scientists have rallied across India to voice their concern about the conference, being held at Lovely Professional University in the state of Punjab.
Researchers in the city of Kolkata and several other cities carried placards and held silent demonstrations over the comments.
"We don't subscribe to their views and distance ourselves from their comments. This is unfortunate," Premendu P. Mathur, the general secretary of Indian Scientific Congress Association, told the AFP news agency. "There is a serious concern about such kind of utterances by responsible people."
The conference is expected to make alterations next year, requiring speakers to submit summaries of speeches, from which they would not be allowed to deviate.
Some of the statements made would chime with comments by leading members of India's ruling Hindu nationalist Bharatiya Janata Party (BJP).
Last year, Satyapal Singh, the minister for higher education, claimed Charles Darwin’s theory of evolution was wrong and vowed to change the national school curriculum as a result.
In 2015, Prime Minister Narendra Modi cited Hindu scriptures as proof that plastic surgery had existed in ancient India.
rc/cmk (Reuters, AFP)