Xiaomi is yet to unveil Mi 11 Lite, and someone has already published an unboxing video of the Mi 11 Lite 4G on YouTube. So, Xiaomi may be planning to announce the device on March 29, but almost all its specifications have already been revealed.
https://www.notebookcheck.net/Xiaomi-Mi-11-Lite-Unboxing-and-hands-on-video-shown-ahead-of-next-week-s-anticipated-launch-of-the-EUR320-smartphone.528853.0.html