Thanks for the reply.
I tried your suggestion in using ES Task Manager but it is not deleting enough cache. Cache is shown as 4MB only.
Apps which are there on the device memory are the ones we cannot move to SD card. Rest all the apps are moved to SD card.
Do you think, rooting the device will allow ES Task manager to look for more cache files? Do you think factory reset will help?
Today again I am getting the same notification “Storage space is running out”.