ICSE Class 9 Answered

The Harappan and the Mohenjodaro cities were known as well-planned cities because:

• The settlement was divided into two sections: Citadel (built on a higher elevation) and Lower Town. The Citadel was walled and separated from the Lower Town. The Lower Town was also walled.
• Bricks used in building the city’s houses were of standardised ratio.
• Roads in the cities were laid out along a grid pattern intersecting each other at right angles.
• The cities of the Indus Valley Civilisation had an advanced system of drainage. Every house was connected to the street drain. House drains emptied themselves into the main drain.  
• The drainage system and drains were covered with bricks or stones. They were provided with inspection holes at regular intervals for cleaning.
• House drains first emptied into sumps into which solid matter settled and wastewater flowed into the street drains.