The decision upsets a 2013 judgment that maintained a pioneer period law, known as area 377, under which gay sex is arranged as an "unnatural offense".
The court has now controlled separation based on sexual introduction is a central infringement of rights.
Campaigners outside the court cheered and some separated in tears as the decision was passed on.
Albeit general assessment in India's greatest urban areas has been agreeable to rejecting the law, there stays solid restriction among religious gatherings and in preservationist country networks.
Happiness in India as gay sex legitimized
Where is gay sex still illegal?
In any case, this decision, from the best court, is the last say in the issue and speaks to an enormous triumph for India's LGBT people group.
What have the judges said?
Thursday's choice was conveyed by a five-judge seat headed by India's active boss equity Dipak Misra and was consistent.
Perusing out the judgment, he stated: "Criminalizing lewd intercourse is silly, subjective and plainly illegal."
Another judge, Indu Malhotra, said she trusted "history owes an expression of remorse" to LGBT individuals for excluding them.
The decision adequately permits gay sex among consenting grown-ups in private.
What is the segment 377?
It is a 157-year-old provincial time law which criminalizes certain sexual goes about as "unnatural offenses" that are deserving of a 10-year imprison term.
Human rights bunches say police have utilized the statute to pester and mishandle individuals from the LGBT people group.
'Perceiving everybody's entitlement to love' 
Despite the fact that it was once in a while summoned when it included consenting grown-ups, segment 377 could be - and was some of the time - utilized as an instrument for provocation. It isn't astonishing then that campaigners are depicting the decision as "another first light for individual freedom".
Be that as it may, in a generally moderate India, where pioneers of all religions have reliably contradicted gay sex, it will at present be a while before mentalities change and the network discovers full acknowledgment.
Yet, laws quite often assume a vital part in evolving outlooks, and by perceiving the network's entitlement to love, the Supreme Court has reestablished the respect denied to them for quite a while.
How could we get to this point?
It's been a convoluted course. An offer to revoke segment 377 was started in 2001 and was batted amongst court and government until 2009 when the Delhi High Court decided for decriminalization.
A few political, social and religious gatherings at that point prepared to reestablish the law and in 2013 the Supreme Court struck down the High Court administering.
 
What has the LGBT response been to the most recent decision?
One of satisfaction given that the network has battled overwhelmingly to strike down the law.
How did host political gatherings respond?
The representing BJP party has said it would leave the choice to the Supreme Court.
Be that as it may, one of its individuals said he was baffled with the decision.
Subramanian Swamy, known for making provocative remarks, stated: "It could offer ascent to an expansion in the quantity of HIV cases."
Then, the principle resistance Congress party has respected the decision, saying they "trust this is the start of a more equivalent and comprehensive society".
Where is homosexuality unlawful?


The 2017 report from the International Lesbian, Gay, Bisexual, Trans and Intersex Association (Ilga) records 72 nations and regions where same-sex connections are still criminalized, despite the fact that that incorporates India before its most recent decision.
The majority of them are in Africa, the Middle East and different parts of South Asia.
The report said homosexuality could at present outcome in capital punishment in eight countries.