The annulment of the Partition of Bengal was done by Lord Hardinge. Let's understand the context and the events leading up to the annulment.

Context:
The Partition of Bengal was a controversial administrative division of the Bengal Presidency of British India that took place in 1905. The partition was proposed by Lord Curzon, the then Viceroy of India, and was implemented on October 16, 1905. The Bengal Presidency was divided into two separate entities - Bengal with its capital in Kolkata and East Bengal and Assam with its capital in Dhaka.

Reasons for Partition:
The main objective behind the partition was to weaken the growing nationalist movement in Bengal, which was seen as a threat to British rule. The British believed that by dividing Bengal along religious lines, they could create a divide between Hindus and Muslims, who had been united in their opposition to colonial rule.

Opposition and Protests:
The partition was met with widespread opposition and protests, particularly from the Hindu community. The Hindus saw the partition as a deliberate attempt to weaken their political and economic influence in the region. The Swadeshi movement was launched as a means of boycotting British goods and promoting Indian-made products as a form of protest against the partition.

Annulment by Lord Hardinge:
Lord Hardinge, who served as the Viceroy of India from 1910 to 1916, played a crucial role in the annulment of the Partition of Bengal. He recognized the growing unrest and the failure of the partition to achieve its objectives. In 1911, he announced the annulment of the partition and the reunification of Bengal.

Reasons for Annulment:
There were several reasons that led to the annulment of the partition. Firstly, the partition had failed to achieve its intended purpose of weakening the nationalist movement. Instead, it had united Hindus and Muslims in their opposition to British rule. Secondly, the partition had caused significant economic disruption and had led to the loss of jobs and livelihoods for many people. Finally, the protests and opposition to the partition had gained momentum and had become a significant challenge for the British administration in the region.

Impact of Annulment:
The annulment of the Partition of Bengal was a significant victory for the nationalist movement in India. It gave a boost to the morale of the Indian population and demonstrated the power of collective resistance against British rule. The annulment also led to the formation of a new province called Bihar and Orissa, which was separated from Bengal.

In conclusion, Lord Hardinge was responsible for the annulment of the Partition of Bengal. His decision was influenced by the failure of the partition to achieve its objectives, the widespread opposition and protests, and the growing nationalist movement in India. The annulment was a significant milestone in the struggle for Indian independence and played a crucial role in shaping the course of Indian history.