Please give information on Harappan civilisationof the Indus Valley.

The Harappan Civilization is the earliest known
civilization in the Indus River Valley of India. The name is derived from Harappa, one
of the cities in the area. The people who comprised that society were known as
Dravidians. Little is known of the society as their language has not yet been
deciphered, and many of their cities and other artifacts are under water. What is known
is that the society was relatively complex. Its cities had roads and streets built on a
grid system; there were at least two major cities with walls, a citadel and granary; and
that they were among the first civilizations to domesticate chickens. There is evidence
of trade with other early civilizations in Mesopotamia and that considerable wealth was
accrued. Many homes had showers and flush toilets that emptied into a central sewer
system, something not frequently seen in early societies. There is no concrete
information on their religious practice, but it appears to involve some type of
fertility practice with a deity represented by a bull.

The
society apparently declined as a result of deforestation as land was cleared to grow
food for a growing population. The land in the area today still requires extensive
irrigation to be arable.