In which year protest for separate state i.e Telangana took a violent phase led to death of many people termed as a biggest tragedy ever .

The Telangana separate statehood agitation saw its most violent phase in 1969, with widespread protests and significant casualties. While renewed protests occurred in 2009-2011, the 'biggest tragedy' with maximum deaths historically refers to the 1969 agitation. The question refers to this earlier phase. The 1970s also saw continued movement activity.