The latitudinal and longitudinal extent of India is about 30°. The
time along the Standard Meridian is taken as the Indian Standard Time. The
Standard Meridian of India passes through Mirzapur in UP which is located at
82°30’ east. The time lag between Arunachal Pradesh (in the east) and Gujarat
(in the west) is about 2 hours. When one moves from south to north, the
latitudinal extent influences the duration of day and night.