The Harappan Civilisation

The Harappan (Indus Valley) Civilization is well known for its remarkable urban planning, drainage systems, and standardized construction practices. One of the key innovations was their use of standardized fired bricks, with specific ratios in dimensions—commonly a 1:2:4 ratio, where:

Height = 1 unit
Width = 2 units
Length = 4 units
This proportion implies that width equals two heights and length equals two widths, making the Assertion (A) completely true. The reasoning behind this brick ratio is rooted in practical engineering. The uniformity and proportionality enabled:

Stronger and more stable walls due to effective bonding patterns (like stretcher and header bonds).
Minimum wastage and more efficient use of space and material.
Faster construction and easy replacement.
Thus, Reason (R) is also true and offers a correct explanation of why such proportions were favored. The combination of strength, durability, and material efficiency was essential in constructing complex urban structures, and these brick proportions enabled that.