The Supreme Court will hear petitions today challenging the Places of Worship Act, 1991, which prohibits changing the character of religious sites as they were on August 15, 1947. Key petitions, including one by Ashwini Upadhyay, seek to invalidate sections 2, 3, and 4, while Subramanian Swamy urges the court to allow claims on disputed sites like the Gyanvapi and Shahi Idgah mosques.