In case the time zone value shown by ubuntu is incorrect, for example Aisa/Calcutta the correct value is UTC + 5.30 but if your system shows only UTC time then follow the step to correct the time of the timezone.
ln -sf /usr/share/zoneinfo/UTC /etc/localtime
here instead of UTC type the zone that is required.
ln -sf /usr/share/zoneinfo/UTC /etc/localtime
here instead of UTC type the zone that is required.
