Read the following source carefully and answer the questions that follow:
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 wastewater 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.
(1) Enumerate one reason, why, Mackay states that” it is certainly the most complete ancient systems yet discovered”
(2) Define the term’ grid pattern’ of the Lower town and state one of its features.
(3)Describe the features of the domestic drainage system.