Describe any three features of Harrapan drainage system

Question 2:Describe any three features of Harrapan drainage system

The correct answer is -i. Harappan cities had the carefully planned drainage system
ii. Roads and streets were laid out along an approximate “grid” pattern,
intersecting at right angles.
iii. Streets with drains were laid out first and then houses were built along
them.
iv. Drainages were made with burned bricks
v. The drains were made of mortar, lime and gypsum.
vi. They were covered with big bricks and stones which could be lifted easily
to clean the drains.
vii. Lime stones were used as cesspits
viii. Any other relevant point
Any three points to be described