The Indus civilization is also called the Indus empire or Harappan civilization; the last name derives from Harappa, the first site of this civilization excavated by modern archaeologists.
Many similarities and striking homogeneity through the region warrant classifying the entire culture under one name. Its dates are approximately 2500–1500 b.c.e. The discovery and scientific excavation of Indus sites backdated the beginning of the Indian civilization by at least 1,000 years.
Neolithic people began to build communities along the Indus Valley in the northwestern part of the Indian subcontinent around 5,000 years ago. Archaeological excavations began in 1921 under the direction of Sir John Marshall on the bank of the Ravi River (a tributary of the Indus) in Sind Province, where railway builders had discovered huge quantities of old fired bricks. They led to the discovery of an ancient city called Harappa that gave its name to the entire civilization.
In 1923 another expedition began to excavate a site called Mohenjo-Daro (meaning "mound of the dead") on the banks of the Indus 400 miles from Harappa, uncovering another major find. Since that time more than 1,000 sites covering approximately 300,000 sq. miles have been investigated.
They include not only the area around the Indus and its tributaries but also northwestern India to Kashmir, the entire Arabian Sea shore including a large seaport called Lothal (which also means "mound of the dead" in the modern language of the region), and as far as Delhi to the east.
Despite advanced agriculture and the use of draft animals to plow the land, the Indus was an urban and commercial culture. It is estimated that 35,000 people lived in Harappa.
The towns had many characteristics in common: a central citadel on a mound surrounded by a brick wall, with a planned city located below, whose streets were laid out in a grid pattern oriented to the points of the compass. The cities were further divided into areas for stores, workshops, and residences.
Working-class dwellings were two-roomed, whereas affluent houses were two-storied centered around a courtyard, with flush toilets and individual wells. The streets had covered sewers, sentry boxes, and public wells on street corners.
Lothal was excavated in 1954. Its specialty was bead manufacturing; a large factory measuring 5,380 sq. feet has been found that used locally produced and imported raw materials to make many sizes of beads for jewelry. The modern town near Lothal is still famous for producing beads for jewelry.
It was also a shipping center with docks and an extensive breakwater. Trade was important for the prosperity of Indus cities. Sumerian and Akkadian cuneiform tablets dating to between 2400 and 2000 b.c.e. mention a place called Dilmun or Telmun in the east that may have been the Indus region.
Indus artisans practiced many crafts: pottery made on wheels, cotton cloths, bronze and copper weapons and tools, and artistic and utilitarian objects made from ivories, various stones, gold, and silver.
Thousands of small, square, and round seals made from steatite have been found throughout the region. Each one has engraved on one surface several characters of pictographic writing together with engravings of animals, plants, or deity-like figures.
Almost 400 separate pictographs have been identified, but not deciphered, and even if they were, each inscription is too short to provide much information. The seals were likely used for sealing merchandise, and the words were probably the names of the merchants. No other examples of Indus writing have survived.
Without a deciphered written script, the Indus civilization is classified as prehistoric. Thus, modern people can only make guesses about many things that concern the Indus civilization. They may have been united into some sort of an empire, as evinced by the uniform size of the bricks used throughout the region.
Since there were no signs of palaces or royal burial sites, the Indus people were probably not ruled by monarchs. Perhaps a college of priests ruled and used the great baths and assembly halls for religious and government ceremonies.
Ritual baths associated with temples were characteristic of Hinduism in later India. Some seals depict a godlike figure with a horned headdress and sitting cross-legged. Some experts speculate that those images could be early images of the later Hindu god Shiva.
Aside from a statue of a deity-like figure and what seem to be female fertility figurines, there are no indications of worship. However, in cemeteries the dead were buried facing the same direction, with artifacts, presumably to use in the next world.
Because of the lack of written records the reasons for the end of the Indus civilization are unclear. What is clear is the decline during its last centuries. One cause of decline was extensive floods, probably caused by widespread deforestation and overgrazing.
Forests were chopped down to provide fuel for firing the billions of bricks used in construction. Denuded land was susceptible to flooding by monsoon rains, which deprived the land of top soil and silted up rivers, raising the river beds and causing floods when rains brought down large quantities of water.
Flooding was exacerbated by geological changes during the beginning of the second millennium b.c.e., which lifted up the coastline of the northern shores of the Arabian Sea. As a result, the Indus waters could not reach the sea and formed shallow lakes.
These changes must have shattered the lives of farmers in the low-lying areas and ruined trade along the coast, which may explain the disappearance of the seals during the last years of the civilization. Flooding also explains the embankments and layers of silt found around Mohenjo-Daro.
In time the floodwaters spilled over the barriers, and the river returned to its course to sea. The process was repeated several times, which must have worn out the people and wrecked the economy, evident by the poorer quality housing and falling civic standards in the last layer of Mohenjo-Daro.
Around 1900 b.c.e. the Indus River changed course and a parallel river, the Saravasti, dried up entirely. The walls and fortifications at Mohenjo-Daro and Harappa also show massive reinforcements during their last phase. The skeletons found scattered helter-skelter at a couple of locations indicate catastrophe, whether human-made or natural.
Harappa and other settlements that had not suffered from previous decline were suddenly abandoned. The last layer of materials excavated from Harappa show poorer quality pottery ware and the cremation of the dead rather than burial, as practiced earlier.
The last layer of habitation at another Indus city called Chanhu-Daro showed fireplaces and chimneys in the houses, a novelty in the Indus Valley, perhaps indicating the culture of newcomers from colder lands.
Beginning around 2000 b.c.e. and for unknown reasons, Indo-European-speaking, seminomadic people from the Eurasian plains began to move from their homelands in a quest for new homes.
One group calling themselves Aryans would move through the mountain passes of modern Afghanistan to the Indus Valley to settle in India. By c. 1500 b.c.e. the Indus civilization had perished and the Aryan age had begun.