The water divide between the Indus and the Ganga river systems lies near:

The low water divide (watershed) between the Indus and Ganga river systems runs roughly through the Ambala region of Haryana, between the Sutlej (Indus system) and the Yamuna (Ganga system).

Features of the divide:

• It is not a high mountain ridge but a slightly raised, almost imperceptible strip of land in the plains, sometimes called the Ambala water divide or the Delhi-Ambala ridge area.
• Rain falling to the west of it drains towards the Indus system.
• Rain falling to the east of it drains into the Yamuna and then the Ganga.
• Because the divide is so low, it has been suggested that rivers in the region may have shifted between the two systems in the past.

The Aravalli connection:

The divide is sometimes described as linked with the northern extension of the Aravalli hills, which continue under the plains towards Delhi.

River capture theory:

Some geographers believe that the Yamuna once flowed westward and later shifted east to join the Ganga.

Ambala:

• Ambala is an important cantonment and railway junction in Haryana.
• It is famous for its scientific instruments industry.
• It lies on the historic Grand Trunk Road.

Importance of the divide:

• It is a key physical boundary in the northern plains, separating the Punjab plains (Indus basin) from the Ganga plains.
• It has historically been important for movement of armies; many famous battles, such as those of Panipat and Tarain, were fought in the region to its south-east.

Why not the other options?

• ✗Delhi lies on the Yamuna, within the Ganga basin.
• ✗Shimla lies in the Himalayas, in the Sutlej basin.
• ✗Ludhiana lies on the Sutlej, in the Indus basin.