The sun rises two hours earlier in Arunachal Pradesh as compared to Gujarat. This causes a time lag of 2 hrs from Gujarat to Arunachal Pradesh to avoid confusion and to have a standard time for reference, The 82.30'Eastern Longitude has been taken as the standard time for the whole country.

Introduction
The selection of the standard meridian of India at 82 degree 30 east has a long history and is based on several factors. In this response, we will explain in detail why this meridian was chosen and its significance.

Geographical Factors
One of the primary reasons for selecting 82 degree 30 east as the standard meridian of India was its geographical location. The meridian passes through the center of the country and is located near the city of Allahabad in Uttar Pradesh. This location was chosen because it is close to the main cities of India and provides a convenient reference point for navigation and mapping.

Historical Reasons
The selection of the 82 degree 30 east meridian can also be traced back to the colonial era. During the British rule, India was divided into several regions, each with its own local time. This made it difficult for railways and other transportation systems to operate efficiently. In 1884, a conference was held in Washington DC to standardize time zones around the world. As part of this effort, the British decided to establish a standard meridian for India to unify the country's time zones. The 82 degree 30 east meridian was chosen as it was close to the local time of the city of Kolkata, which was the center of British administration in India at the time.

Modern Significance
Today, the 82 degree 30 east meridian continues to be an important reference point for navigation, mapping, and timekeeping in India. It is the basis for the Indian Standard Time (IST), which is used throughout the country. The meridian also serves as the basis for many geographical and scientific surveys conducted in India.

Conclusion
In conclusion, the selection of the 82 degree 30 east meridian as the standard meridian of India was based on a combination of geographical, historical, and practical factors. Its location at the center of the country and its historical significance as a reference point for timekeeping and navigation make it a crucial element of India's geography and infrastructure.