India must overhaul its antiquated laws and cumbersome legal system which are increasingly being misused to silence dissent in the Hindu majority country, a global writers' group said in a report on Monday.
Hardline Hindu groups have been accused of fomenting intolerance of religious and other minorities since nationalist Prime Minister Narendra Modi swept to power at general elections in 2014.
Pen International said a survey of authors, lawyers, activists and journalists this year found that this "culture of intolerance has taken root in India and has grown more menacing".
Defamation, sedition and those laws pertaining to hate speech were being misused by "intolerant individuals and groups" to severely restrict freedom of expression, it said.
"Their (those surveyed) accounts suggest that the unchecked abuse of India's vague and overbroad legislation, and its inefficient legal system, have helped to create a chill within Indian society and throughout its public sphere," the report, also by PEN Canada and the University of Toronto's law faculty, said.
A student union leader at a prestigious New Delhi university was arrested and charged with sedition earlier this year for allegedly shouting anti-India slogans.
The arrest brought thousands of students and teachers onto the streets in protest and fuelled mounting concern about freedom of speech.
The British-era sedition law carries a maximum penalty of life in prison. Prosecutions are rare but it has frequently been used against critics of the government of the day.
Several authors last year returned a prestigious award in protest at what they called government inaction over the murder of atheist scholars and the lynching of a Muslim man suspected of eating beef.
Those interviewed for the report also spoke of endless harassment and threats, particularly online, to silence criticism.
The report said writers and journalists now faced frequent "implied and direct threats".
"Some face more immediate violence from the groups and individuals who wish to silence them. These censors are seldom reprimanded, much less prosecuted," it said.