The Nawalparasi district and the international border of India are the Narayani / Gandaki River, as per the Sugauli Treaty of 3. As mentioned in the treaty, Narayani / Gandaki is on the west, Nepal and India on the east.
The Susta settlement of the Sugauli treaty was west of the Narayani / Gandaki river. When the river's torrent changed, the river started flowing from the west of the Susta and the sluggishness fell to the east. From that time, the Nepal-India border dispute began.
Especially after India claimed the Nepalese land east of Narayani as its own, the dispute started there. According to the 'fixed boundary principal' of the boundary, the boundary line will not change even if the river changes torrents or otherwise causes damage to the land.
According to the same principle, boundaries have been set between Nepal and India in the Mechi River. However, India claims to be the 'fixed boundary principal' and owns the slums, bhediyari and villages of Nawalparasi. The village was located west of the Narayani River during the Treaty.
However, it is now located east of Narayani. The picture of how the river changed the course of the river between 1909 and 9 can be seen in the picture below.
The red arrows on the map show the change in the path of the river, while the blue line shows the location of the river before moving but not the river. Changes in the range of 19–1 and the flowing line of the Suguli Treaty before 1949 are also shown.
In these photographs taken from the satellite, the river appears to have changed the course and eased the slack. However it can be further debated by field validation and still looking at old maps and satellite imagery.
Looking at the picture, the situation in the slums and lakeside has not changed. Continuing settlement since 1949 means that the river has changed its course, not cutting the land.
The NAPI Department has issued a map with the technical support of JICA as the basis for the Sugauli Treaty as a basis study (see map below). It has been a long time since the Government of Nepal has established rehabilitation, police post and school for the development of sluggishness.
Instead of fixing the problem on the basis of a 'fixed boundary principal', India is invading rather than bringing in Indians. There is no substitute for India being ready to resolve border disputes on the basis of a 'fixed boundary principal' like in the Mechi River.