One of the most astonishing features of the Harappan civilisation was the drainage system of their cities. It was very carefully planned. Some of its features are: The streets and towns in the cities were laid out in a grid pattern intersecting at the right angles. The streets had proper drains at regular intervals having a fixed pattern. Every house was connected with the drainage system for the carrying of the waste to the disposal centre. There was cesspits at regular intervals so that any issue with the blockage of the drainage can be easily resolved. The drainage system of the Harappan cities was the sign of the engineering genius of the people of Harappa.