Location of India on the globe
India lies fully in the northern and eastern hemispheres, in South Asia. The Himalaya lie to the north. The Indian Ocean, Arabian Sea and Bay of Bengal lie to the south, west and east. This central place on the Indian Ocean has helped trade for thousands of years.
Size of India
- Area: about 3.28 million km² (32.8 lakh km²).
- That is about 2.4% of the world's land area.
- India is the 7th largest country (after Russia, Canada, USA, China, Brazil, Australia).
- Land boundary about 15,200 km; coastline of the mainland plus islands about 7,500 km.
- Big size = many kinds of land, climate, soils, plants and people.
Latitude and longitude extent
Latitude (north–south)
Mainland: 8°4′N to 37°6′N, about 29°. North–south length about 3,214 km. The southern tip of the islands, Indira Point, is near 6°45′N.
Longitude (east–west)
68°7′E to 97°25′E, also about 29°. East–west width about 2,933 km.
Why is the N–S distance larger if both spans are ~29°?
Lines of latitude stay the same distance apart (about 111 km per degree). Lines of longitude come closer together as you go away from the equator, so each degree of longitude is shorter in India.
Tropic of Cancer
23°30′N passes through eight states from Gujarat to Mizoram. South of it: tropical zone. North of it: sub-tropical/temperate.
Standard time (IST)
The Earth turns 360° in 24 hours, so 1° = 4 minutes. From 68°7′E to 97°25′E is about 29°, so sun time in the far east is about 2 hours ahead of the far west.
If each town kept its own sun time, trains and offices would be confused. So India chose one standard meridian: 82°30′E, passing near Mirzapur (Uttar Pradesh). It is roughly in the middle of India's longitude range.
IST = 82.5 × 4 = 330 min = GMT + 5 h 30 min. Standard meridians are usually chosen as multiples of 7°30′ so the difference from GMT is in whole half-hours.
Key formulas and definitions
- 1° longitude = 4 minutes of time
- Time difference = (difference in longitude) × 4 min
- IST = GMT + (82.5 × 4) min = GMT + 5 h 30 min
- Latitude extent: 8°4′N – 37°6′N; Longitude extent: 68°7′E – 97°25′E
- Area ≈ 3.28 million km² ≈ 2.4% of world land
Worked examples
1. What is the sun-time difference between 68°7′E and 97°25′E?
Difference = 97°25′ − 68°7′ = 29°18′ ≈ 29.3°. Time = 29.3 × 4 = 117.2 min ≈ 1 h 57 min, about 2 hours.
2. When it is 12:00 noon GMT, what is the time in India?
IST = GMT + 5:30, so it is 5:30 pm in India.
3. At 12:00 noon IST, what is the sun time at Mumbai (about 72.8°E)?
Difference = 82.5 − 72.8 = 9.7°. 9.7 × 4 ≈ 39 min. Mumbai is west, so its sun time is behind: 12:00 − 0:39 = 11:21 am.
4. At 12:00 noon IST, what is the sun time at Kohima (about 94.1°E)?
Difference = 94.1 − 82.5 = 11.6°. 11.6 × 4 ≈ 46 min. Kohima is east, so ahead: 12:46 pm.
5. Why is India's north–south length (3,214 km) more than its east–west width (2,933 km) when both spans are about 29°?
A degree of latitude is always about 111 km. A degree of longitude shrinks away from the equator, so 29° of longitude at India's latitudes is shorter.
6. Why is 82°30′E chosen and not 80°E?
82°30′ is a multiple of 7°30′ (11 × 7°30′), so IST differs from GMT by an exact 5½ hours; it also lies near the middle of India's longitudes.
Common mistakes
- Saying India's extent is from 8°4′N to 37°6′S. Both ends are north of the equator.
- Using 15 minutes per degree. It is 4 minutes per degree (15° = 1 hour).
- Adding time when moving west. West is behind (subtract), east is ahead (add).
- Thinking the standard meridian passes through Delhi or Allahabad city. It passes near Mirzapur.