82°30'E
Explanation
Indian Standard Time (IST) is the time observed throughout India and Sri Lanka, with a time offset of UTC+05:30. To ensure a uniform time across the country, a central meridian is selected to determine the standard time.
Detailed Analysis:
- 82°30'E : This longitude is designated as the Standard Meridian of India. It passes through Mirzapur (near Prayagraj/Allahabad) in Uttar Pradesh. It was selected because it roughly bisects the country longitudinally, balancing the time difference between the western and eastern extremities.
- 68°7'E : This represents the westernmost longitude of India, located in the Kutch district of Gujarat (Ghuar Mota).
- 97°25'E : This represents the easternmost longitude of India, located in the Anjaw district of Arunachal Pradesh (Kibithu).
- 23°30'N : This represents the Tropic of Cancer. It is a latitude, not a longitude, and it divides India geographically into the tropical southern half and the subtropical northern half.
Key Takeaway:
The 82°30'E longitude is the basis for Indian Standard Time, placing India 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT). This single time zone is maintained to avoid administrative confusion, despite a longitudinal gap causing a time difference of nearly two hours between Gujarat and Arunachal Pradesh.