YU Yureka stuck at Cyanogen logo
Try booting into TWRP if you have it installed, if you don't have TWRP installed on your device you can follow the instructions here:   https://twrp.me/yu/yuyureka.html

In TWRP you should be able to back up your data onto a computer. When your data is safe you could either go to a service center and see if they can fix your phone or you could try flashing a new ROM and see if that fixes the problem. You can find many tutorials on how to flash a ROM with TWRP online.

Cyanogen download can be found here:
https://cyanogenupdatetracker.com/downloads/