An Indian court has ended a decades-old ban on author Salman Rushdie's controversial novel The Satanic Verses after authorities were unable to locate the original order restricting its imports.

Rushdie, 77, lived in hiding for years after Iran's first supreme leader Ayatollah Ruhollah Khomeini ordered his killing for what he deemed the book's blasphemous nature.

The British-American writer has since become an outspoken defender of free speech but in India, where he was born, his most infamous work has been banned since 1988, the year of its publication.

This week, however, the Delhi High Court quashed the ban in a ruling on a case first brought in 2019 by Sandipan Khan, a reader who wanted to buy the book.

The court said "none of the respondents" could produce the original notification banning the book and that its decision now allows Khan to purchase it from abroad.

"We have no other option except to presume that no such notification exists," the court said in its order, published this week.

Viking Penguin published The Satanic Verses in September 1988 to critical acclaim.

The book is set by turns in London under Conservative British prime minister Margaret Thatcher and ancient Mecca, Islam's holiest site.

But it was deemed blasphemous and sacrilegious by many Muslims over references to verses alleged by some scholars to have been an early version of the Koran and later removed.

Indian Prime Minister Rajiv Gandhi banned the import of the book a month after its publication, hoping to win Muslim support ahead of elections. Around 20 countries went on to outlaw it.

While India is a Hindu-majority country, the world's most populous country includes more than 200 million Muslims. 

Months before his death in 1989, Iranian leader Khomeini issued a fatwa, or religious decree, urging "Muslims of the world rapidly to execute the author and the publishers of the book".

A $2.8-million bounty was put on the head of Rushdie, who was immediately granted police protection in Britain and spent almost 13 years living in safe houses under a pseudonym.

Rushdie gradually emerged from his underground life in 1991, but his Japanese translator was killed in July that year.

His Italian translator was stabbed a few days later and a Norwegian publisher shot two years later, although it was never clear the attacks were in response to Khomeini's call.