Consider the following statements about the town planning during Harappan Civilisation.
1. The towns of Harappa and Mohenjodaro were divided into two parts citadel for ruling class and lower town for common people.
2. The roads cut across one another almost at right angles.
3. Water flowed from the houses to the streets, which had drains, sometimes covered with bricks and stone slabs.
4. Burnt bricks were used in Harappan cities.
Which of the statements given above is/are correct?