The correct option is 1 and 2 only.
Explanation
The Indus Valley Civilization is characterized by remarkable uniformity in urban planning, particularly in the standardization of construction materials across vast geographical areas.
- Statement 1 is Correct: Harappan settlements utilized both sun-dried and baked (burnt) bricks. While sun-dried bricks were commonly used for platforms and massive walls, baked bricks were extensively used in drains, wells, and water-exposed structures due to their durability and water resistance.
- Statement 2 is Correct: The bricks were manufactured according to a standardized ratio. This uniformity suggests a high degree of organization and possibly a centralized system of weights and measures.
- Statement 3 is Incorrect: The dimensions of the bricks were not equal; rather, they followed a specific ratio of 1:2:4 regarding thickness (height), breadth, and length. Consequently, the length was four times the height, and the breadth was two times the height.
- Statement 4 is Incorrect: This standardized brick ratio was not confined to Mohenjodaro and Harappa. It was a widespread feature observed in numerous settlements across the civilization, reflecting a shared architectural culture.
Key Takeaway: A distinctive feature of Harappan architecture is the use of standardized bricks with a dimension ratio of 1:2:4 (Thickness : Breadth : Length) across the civilization.