The pacific manifestations in India lead by Mahatma Gandhi were succesfull because they protested in many different ways, and with many different people, from farm workers to politicians, everyone took action in different ways to assure India´s independence, from not paying taxes for farm lands to producing salt without government permission, Indians got united to attack pacifically the Brithis colonialism.
Due to the fact the war was fought on the colonist's land, they knew the land better than the British and could play defensive. The colonists also used guerilla warfare a lot, securing a definite American victory.