Let’s see some part of history.
In September 1814, the British Empire sent a troop of 16000 to invade Nepal under General Morley, General Wood, General Gillespie, and General Octhterlony at different frontiers. Among them only General Gillespie was killed on the fort of Kulunga and the other three Generals were facing heavy resistance from the Nepalese army. The only notable success scored by the British was achieved by the fourth column, led by General Ochterlony. After a long and difficult campaign against the Nepali force under Amar Singh Thapa, Ochterlony forced Amar Singh Thapa to agree at Malaun to terms under which the Nepali army retired with their arms and the territory between the Kali and Sutlej rivers came under the control of British.
During this period of war against the Britsh, Nepal was in search of ally against the British. Kathmandu sent letters to Amban Lhasa for transmittal to the Emperor in Peking. Nepal’s appeal to various Indian states was no more successful. Bhimsen sent envoys to Mahrattas and Sikhs to urge them to stand with Nepal against the British, and to Deb Raja of Bhutan. All attempts of Nepal were failing and the British were starting their second campaign to invade Nepal under General Ochterlony. He was able to outflank the main defense position at Makwanpur thus clearing the major obstacle towards the road to Kathmandu. With the collapse of the main defense line, Kathmandu Durbar sent Chandra Shekhar Upadhyay to Ochterlony’s camp with a copy of the Sugauli treaty. At first, he refused but on March 4, 1816 he agreed for a treaty which constituted a serious loss to Nepal.
The most important provisions of the treaty were: