The five-judge constitution bench headed by Chief Justice of India (CJI) J.S. Khehar, deciding on the verdict, was seemingly split on the legality of the practice.
If law doesn't come in force in six months, then SC's injunction on triple talaq will continue.
The bench had heard seven pleas, including five separate petitions filed by Muslim women challenging the prevalence of triple talaq. Chief Justice Khehar, on behalf of himself and Justice S. Abdul Nazeer, who were in the minority, said instant divorce could not be held unconstitutional because it was part of Muslim personal law. That is why while upholding the practice, they injuncted that a legislation is brought about.
Dubbing it as a "path-breaking judgement", Rohatgi said the stand of the government was "completely vindicated" and the judgement has restored the dignity of the Muslim women who can now march to progress like other citizens of the country.
Triple talaq (divorce) is a Muslim practice that allows Muslim men to leave their wives effective immediately just by saying the word "talaq" three times.
Modi has addressed the topic numerous times in public speeches, pledging to protect the right to equality of all women.
Triple talaq was already ruled unconstitutional by the Supreme Court in a number of cases, including in February 2015.
India's right-wing government is considered to be largely in favor of banning triple talaq.
The Muslim Personal Law Board had opposed any court intervention, arguing that the court must keep out of matters of faith.
Justices Nariman and Lalit said that triple talaq was manifestly arbitrary and the 1937 Act, which recognises it, was unconstitutional and struck it down. The prime minister and our government have been sensitive to Muslim women's concerns.
The court reserved its verdict after a six-day marathon hearing during the summer vacation. "Triple talaq is a part of our religion and of sharia", Kamal Faruqui, a member of the executive committee of the All India Muslim Personal Law Board which advocates for Muslim law, said.