Q.Read the following source carefully and answer the questions that follow : (1+1+2=4) The most ancient system yet discovered About the drains, Mackay noted : "It is certainly the most complete ancient system as yet discovered." Every house was connected to the street drains. The main channels were made of bricks set in mortar and were covered with loose bricks that could be removed for cleaning. In some cases, limestone was used for the covers. House drains first emptied into a sump or cesspit into which solid matter settled while waste water flowed out into the street drains. Very long drainage channels were provided at intervals with sumps for cleaning. It is a wonder of archaeology that "little heaps of material, mostly sand, have frequently been found lying alongside drainage channels, which shows... that the debris was not always carted away when the drain was cleared". From Ernest Mackay, Early Indus Civilisation, 1948 Drainage systems were not unique to the larger cities, but were found in smaller settlements as well. At Lothal for example, while houses were built of mud bricks, drains were made of burnt bricks. (31.1) Analyse the possible reason behind the uniformity in the drainage systems across the Harappan cities.

Concept: Urban planning and civic infrastructure in the Harappan Civilization

(31.1) Reason for uniformity:

The uniformity across Harappan cities—standardized brick sizes, consistent street layouts, and identical drainage principles—points to centralized planning and strong administrative control. Either a unified authority enforced building codes, or a shared cultural/technical knowledge system ensured replication of best practices across settlements, reflecting a sophisticated, organized society. …

The Harappan drainage system is one of the most striking features of the Indus Valley Civilisation, revealing a society that prioritised sanitation and urban planning at a scale unmatched in the ancient world. When we see the same design principles—covered brick drains, sump pits, street connections—repeated across cities separated by hundreds of kilometres, we are looking at something far more significant than coincidence. This uniformity, the maintenance evidence, and the system's sheer sophistication tell us about the values and capabilities of this civilisation.

31.1 Reason behind uniformity in drainage systems

The remarkable consistency across Harappan cities points to centralised planning and shared technical knowledge.

When Mohenjo-daro, Harappa, Lothal, and smaller settlements all follow the same drainage blueprint—brick-lined channels, removable covers, sump pits before street connection—it suggests either a central authority dictating urban standards or a widely disseminated body of engineering expertise. The Harappans likely had:

• Standardised building codes enforced across the civilisation, much like modern municipal regulations
• Trained engineers or architects who moved between cities or whose knowledge was systematically transmitted
• A shared understanding that public health required uniform, city-wide solutions rather than individual household arrangements

The use of burnt bricks for drains even in Lothal, where houses were mud brick, shows a deliberate choice: drainage infrastructure was too important to compromise. This wasn't accidental uniformity but planned civic engineering on a civilisational scale.

31.2 Implications of sand heaps alongside drains

The "little heaps of material, mostly sand" are direct archaeological evidence of regular maintenance and cleaning.

Mackay's observation is crucial because it captures a moment frozen in time: someone cleaned these drains, removed the debris, and left it beside the channel—perhaps to be carted away later, or simply as evidence of the work done. This tells us:

• The drainage system was actively maintained, not just built and abandoned
• There was likely a civic workforce or system responsible for sanitation—early municipal services
• The Harappans understood that drains required periodic cleaning to function, showing practical hydraulic knowledge

The fact that debris "was not always carted away" might seem like a flaw, but it actually humanises the civilisation: maintenance happened, even if not always perfectly executed. It proves the system was a living, functioning part of daily urban life.

31.3 Impact of the Harappan drainage system

The drainage system had profound impacts on both the civilisation itself and our understanding of ancient urban development.

1. Public health and quality of life

The comprehensive drainage network would have dramatically reduced waterborne diseases and maintained hygiene in densely populated cities. By separating solid waste (in sump pits) from liquid waste (flowing to street drains), the Harappans minimised contamination of living spaces. This infrastructure supported:

• Higher population densities without epidemic disease
• Cleaner streets and reduced foul odours
• A standard of urban sanitation not seen again until Roman times, and in some regions not until the modern era

2. Evidence of sophisticated governance

The system's scale and uniformity reveal a society with:

• Strong civic administration capable of planning, funding, and maintaining public works across generations …