Architecture:
City planning: The overall layout of the Indus is based on a grid of right angles. Large streets run in straight lines in north-south directions and are crossed by smaller streets in an east-west direction. The large streets were 33 feet wide and smaller streets ranged from 9 to 12 feet in length. The division of space into separate blocks is seen not only in the layout of the streets but also in house plans, the designs on pottery as well as the diagrams on seals. In contrast to this, the layout of early Mesopotamian cities was quite irregular. The idea of settlement planning was already well established before 2600 BC and is seen in all the settlements through the Indus. Each city is made up of a series of walled sectors or mounds with massive brick gateways. The orientation of the Indus cities along a north-south and east-west direction was probably linked to religious beliefs.
Drainage: Well laid out streets and side lanes with drains are one of the outstanding features of the Indus cities, even in smaller towns and villages. The drains, made of brick, connected the baths and toilets of private houses to medium sized drains in the side streets. These flowed into larger drains in the main streets that were covered with brick and or stone blocks, which were removable for cleaning purposes. Corbelled arches were built to allow larger drains to cut beneath streets and buildings until they reached the city wall, throwing the water out onto the outlying plain. At regular intervals along the main sewage drains, were rectangular sump pits for collecting solid waste. These sump pits were cleaned on regular basis. Wells: Wells and reservoirs were built within the cities to ensure drinking and bathing water. It has been estimated that Mohenjo-Daro may have had 700 wells, whereas Harappa may have had as few as 30. It could be