Distinguishing aspects of Harappan town planning are as follows:

• The streets were wide, the main street being ten metres wide and dividing the town into rectangular and square blocks.
• There were lamp-posts at intervals. They used burnt bricks of good quality and the unique feature of this brick was its identical ratio of 1:2:4 in terms of thickness:width:length across all Harappan structures.
• Equally striking was the uniformity in the average size of bricks — 7 × 14 × 28 cm3 for houses and 10 × 20 × 40 cm for city walls.
• They had an excellent drainage system — drains were made of mortar, lime and gypsum and covered with large brick slabs for easy cleaning.
• Houses were often of two or more storeys, though varied in size but quite monotonous. No window faced the streets and the houses had tiled bathrooms.
• Some houses had their own wells.

Source: NCERT