Lagging

When i open this world everything is okay and i am on 60fps but in like 20 seconds my fps drops to 0 and this is for this world. The other worlds are normal and i dont know what can cause that problem. This just happened instantly and i tried to remove a bugged chunk to see of that was a problem using mcedit but it didnt help. So if you know how to solve this problem please tell me, I will be very thankfull