Section 377 of the Indian Penal Code is a colonial era law which criminalises sexual activities "against the order of nature". It is widely regarded as criminalising homosexuality. It was declared discriminatory and unconstitutional and overturned by the Delhi High Court in 2009, but this judgement was reversed by the Supreme Court (SC) in December 2013. The SC's decision included a number of confused arguments and was widely criticised, including by Congress and the Aam Aadmi Party. However it was was welcomed by the RSS and the BJP which claimed that "western culture cannot be brought to India" (video).
A number of religious leaders and godmen came out in Support of Section 377, including Baba Ramdev who claims he can "cure homosexuality, VHP leader Om Prakash Singhal who said, "Homosexuality is against Indian culture, against nature and against science", and various religious leaders of minority communities, including Maulana Madni of the Jamiat Ulema, Rabbi Ezekiel Issac Malekar, and Reverend Paul Swarup.
In September 2018 Section 377 was ruled unconstitutional by the Supreme court.
References:
• Section 377 on The Wire.
• Commentary by the Lawyers Collective.