53. Which Amendment Acts extended the period of reservation for SCs and STs in legislatures from ten years to eighty years (until 2030)

The 8th Amendment Act of 1959, 23rd Amendment Act of 1969, 45th Amendment Act of 1980, 62nd Amendment Act of 1989, 79th Amendment Act of 1999, 95th Amendment Act of 2009, and the 104th Amendment Act of 2019 extended the period.