What is the Susta border dispute about?

Shrestha: In the Susta area, India has encroached on about 14,000 hectares of land over a period of 72 years. The intrusion happened in stages, the latest being on November 22, 2007.
Q: What do you think are the reasons behind the arguments over the border with India?
Shrestha: The main reason is that 595 kilometers of the 1,808-kilometer-long Nepal-India border is defined by rivers—such as the Mechi in the east, Mahakali in the west, and the Narayani in the Susta area, which demarcates a 24-kilometer stretch of the international frontier. The rivers keep changing course and that gives rise to arguments.