India's top court has upheld a law which criminalises gay sex, in a ruling seen as a major blow to gay rights, BBC reported.The Supreme Court ruling reverses a landmark 2009 Delhi High Court order which had decriminalised homosexual acts.The court said it was up to parliament to legislate on the issue.According to Section 377, a 153-year-old colonial law, a same-sex relationship is an "unnatural offence" and punishable by a 10-year jail term.Several political, social and religious groups had petitioned the Supreme Court to have the law reinstated in the wake of the 2009 court ruling.'Black day'"It is up to parliament to legislate on this issue," Justice GS Singhvi, the head of the two-judge Supreme Court bench, said in Wednesday's ruling."The legislature must consider deleting this provision (Section 377) from law as per the recommendations of the attorney general," he added.Gay rights activists have described Wednesday's Supreme Court ruling as "disappointing" and said they will approach the court to review its decision."Such a decision was totally unexpected from the top court. It is a black day," Arvind Narrain, a lawyer for the Alternative Law Forum gay rights group, told reporters."We are very angry about this regressive decision of the court," he said."This decision is a body-blow to people's rights to equality, privacy and dignity," G Ananthapadmanabhan of Amnesty International India said in a statement."It is hard not to feel let down by this judgement, which has taken India back several years in its commitment to protect basic rights," he added.However, the ruling has been welcomed by religious groups, particularly leaders of India's Muslim and Christian communities, who had challenged the Delhi High Court order."The Supreme Court has upheld the century-old traditions of India, the court is not suppressing any citizen, instead it is understanding the beliefs and values of the large majority of the country," Zafaryab Jilani, member of the All India Muslim Personal Law Board, told BBC Hindi.In its 2009 ruling, the Delhi High Court had described Section 377 as discriminatory and said gay sex between consenting adults should not be treated as a crime.The ruling was widely and visibly welcomed by India's gay community, which said the judgement would help protect them from harassment and persecution.ANN.Az