NEW DELHI: As the Supreme Court (SC) is likely to pronounce its verdict on pleas challenging the validity of Section 377 of the Indian Penal Code (IPC) on Thursday, here is an explainer on what it means.Section 377 of the IPC refers to 'unnatural offences' and says whoever voluntarily has carnal intercourse against the order of nature with any man, woman or animal, shall be punished with imprisonment for life, or with imprisonment of either description for a term which may extend to 10 years, and shall also be liable to pay a fine.The section came into force in 1861 during the British rule of India (modelled on the Buggery Act of 1533) which criminalised sexual activities "against the order of nature", including homosexual activities.The issue of Section 377 was first raised by an NGO, Naaz Foundation , which had in 2001 approached the Delhi high court that had decriminalised sex between consenting adults of the same gender by holding the penal provision "illegal".This 2009 judgement of the high court was overturned in 2013 by the Supreme Court which had also dismissed a review plea. It had in 2013 restored the criminality of the sexual relationship between persons of the same sex, after the Delhi high court' had decriminalised it in 2009.On August 24, 2017, the SC had upheld the Right to Privacy as a fundamental right under the Constitution . The SC also had called for equality and condemned discrimination, stating that the protection of sexual orientation lies at the core of the fundamental rights and that the rights of the LGBT population are real and founded on constitutional doctrine.In January 2018, a three-member SC bench heard a petition filed by five people asking the apex court to revisit the Naaz Foundation judgement. The case was referred to a larger bench and help was sought from the Centre also.The apex court then on July 17 reserved its verdict on whether to decriminalise Section 377 or not.The SC will decide whether the section criminalising consensual gay sex is valid or not on Thursday.