Topic: India's Location, Extent, Boundaries and Standard Time
HEADLINE: TNPSC Group IV Geography: India's Location, Latitudes, Longitudes, IST and Coastline – Complete Short Notes
India is in southern Asia. Its location, coordinates, borders and standard time are important for map-based and fact-based TNPSC questions. This lesson covers the location-and-extent part of geography; mountains, plains and rivers will be taught separately.
1. India's location and area • India lies in the Northern and Eastern Hemispheres. • Area: approximately 3,287,263 square kilometres (3.28 million sq. km). • India is the world's seventh-largest country by area and covers about 2.4% of the world's land area. • The Himalayas lie to the north; the Arabian Sea is to the west, the Bay of Bengal to the east and the Indian Ocean to the south. • A peninsula is land surrounded by water on three sides. Southern India is a peninsula.
2. Latitudes and longitudes • Latitude measures angular distance north or south of the Equator. It helps us understand climate and temperature zones. • Longitude measures angular distance east or west of the Prime Meridian. It helps determine local time. • Mainland India extends from 8°4′ N to 37°6′ N latitude and from 68°7′ E to 97°25′ E longitude. • North–south extent: about 3,214 km. East–west extent: about 2,933 km.
3. Tropic of Cancer: eight states • School textbooks usually express the Tropic of Cancer as 23½° N latitude (its precise present-day position is approximately 23°26′ N). • It passes through eight Indian states from west to east: Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram. • Memory aid: Gu–Ra–MP–Ch–Jh–WB–Tri–Mi. • The Tropic of Cancer does not pass through Tamil Nadu.
4. Indian Standard Time (IST) • India's Standard Meridian is 82°30′ E longitude (82.5° E). It passes near Mirzapur in Uttar Pradesh. • IST = UTC + 5 hours 30 minutes. • Earth rotates 360° in 24 hours. Therefore, 15° of longitude corresponds to one hour and 1° to four minutes of local solar time. • Gujarat and Arunachal Pradesh have nearly two hours of difference in local solar time, but India uses one standard time. • Example: If it is 06:00 UTC, it is 11:30 IST. • Do not confuse the Tropic of Cancer (latitude 23½° N) with the Standard Meridian (longitude 82½° E).
5. Boundaries and neighbouring countries • The conventional textbook figure for India's land frontier is approximately 15,200 km. • Pakistan is to the west; China, Nepal and Bhutan are to the north; Bangladesh and Myanmar are to the east. • Many Indian school textbooks also list Afghanistan as a seventh land neighbour. This refers to India's claimed boundary through a Kashmir region not currently under Indian administrative control; it is not a directly administered border. • Maritime neighbours include Sri Lanka and the Maldives. • As of 2026, India has 28 states and 8 Union Territories. Older textbooks may show 29 states and 7 UTs; do not use those old counts as current facts.
6. India's coastline: important 2025 revision • Older textbook coastline length (including islands): 7,516.6 km. • New official measurement notified on 29 April 2025: 11,098.81 km. • The difference comes from more detailed maps and a revised measurement method. It does not mean the coastline physically grew by thousands of kilometres overnight. • Gujarat has the longest coastline among states under the revised figures: 2,340.62 km. • Revised Tamil Nadu coastline: 1,068.69 km; Andhra Pradesh: 1,053.07 km. • For exam questions, distinguish the older textbook figure from the revised 2025 government figure.
7. Southernmost points and island groups • The southernmost point of all Indian territory is Indira Point on Great Nicobar Island (approximately 6°45′ N). • The southernmost point of mainland India is Kanniyakumari (Cape Comorin), Tamil Nadu. • Lakshadweep is in the Arabian Sea and consists mainly of coral islands. • Andaman and Nicobar Islands are in the Bay of Bengal. • Island: land surrounded by water on all sides. Peninsula: land surrounded by water on three sides.
8. Tamil Nadu relevance • Tamil Nadu is on India's southeastern coast, facing the Bay of Bengal. • The coastal stretch from Chennai towards Point Calimere is associated with the Coromandel Coast (சோழமண்டலக் கடற்கரை). • Palk Strait and the Gulf of Mannar separate Tamil Nadu from Sri Lanka by sea. • Kanniyakumari is the southern tip of mainland India, not the southernmost point of the entire Indian territory. • Under the revised national coastline figures, Tamil Nadu has the second-longest state coastline after Gujarat.
9. Map-reading practice On an outline map of India, locate Gujarat, Arunachal Pradesh, Kanniyakumari, the 82°30′ E meridian near Mirzapur, the Tropic of Cancer, Sri Lanka, Lakshadweep, Andaman and Nicobar, the Arabian Sea and the Bay of Bengal.
10. Common exam traps • 3,214 km = north–south extent; 2,933 km = east–west extent. • Indira Point = southernmost point of India; Kanniyakumari = southernmost mainland point. • 82°30′ E = Standard Meridian; 23½° N = Tropic of Cancer. • The Tropic of Cancer does not cross Tamil Nadu. • 7,516.6 km = older coastline figure; 11,098.81 km = revised 2025 figure.
11. One-minute revision India: Asia; Northern/Eastern Hemispheres; seventh-largest country; area about 3.287 million sq. km; Tropic of Cancer crosses eight states; IST uses 82°30′ E and UTC+5:30; Indira Point is the southernmost point; Kanniyakumari is the southernmost mainland point; revised coastline is 11,098.81 km.
12. Textbook reference and book-back progress • Reference: Tamil Nadu Samacheer Kalvi Class 10 Social Science, Geography Unit 1, 'India – Location, Relief and Drainage' (visible 2019 printed-edition exercise sections). • Identified for the entire chapter: 10 MCQs + 5 matching pairs + 6 give-reasons prompts + 4 comparisons + 5 short answers + 3 paragraph answers + 3 map exercises = 36 core practice items; plus 5 activities. Total: 41 items. • Verified exercises completed: 0/36 core items; activities completed: 0/5. These are counts for the accessible 2019 edition only. The complete 2026–27 government edition has not yet been checked. • Today's topic covers only location, extent, borders and standard time. The Himalayas, Northern Plains, plateaus, coastal plains, rivers and drainage remain pending for future lessons. • Some administrative and coastline figures in the older textbook are outdated; updated government figures are identified separately in this lesson. • Tonight's 7 PM practice will include five General Studies questions from this lesson. Questions will not be labelled TNPSC PYQs without verification against official examination papers and final keys.
Spaced revision: 17, 19, 23 and 30 October 2026 (1/3/7/14 days).
