Answer:
Political Cause
Most of the defeated kings of Baise and Chaubise states went to take asylum in India. They wanted to regain their lost territory. therefore, they used to provide secret information to British-India and encouraged to attack Nepal.
Bhimsen Thapa was the Prime Minister of Nepal during Anglo-Nepal war. he was against the British imperialism. he wanted to chase the British away not only from India but from whole Ais. He negotiated with the Indian states like Punjab, Maratha, Gwaliyar, Burma etc. to form a united organization of Asia against the British imperialism. Bhimsen Thapa was strengthening the power of Nepali troops by increasing weapons and providing trainings to soldiers. The British were alert of such activities and plan of Bhimsen Thapa and wanted to colonize Nepal too.
Economic Cause
British wanted to extend their trade with Tibet through Nepal
The British didn't like the act of strengthening Nepali troops.
They were attracted to Nepal's richness in natural resources and minerals.
