Hello Mahi, You go to www.wikipedia.org, type in "deepest lake", press "return" and read the detailed result. This is how everyone else in the world (except the Chinese) gets such an answer.

lake baikal in russia

Average depth of the lake Baikal is 730 meters, but the deepest mark - 1,620 meters

Lake Baikal is the world's oldest and deepest lake. As the most voluminous freshwater lake in the world, with an average depth of 744.4 m (2,442 ft), Lake Baikal contains roughly 20% of the world's surface fresh water.