Deputy Prime Minister of India Vallabhbhai Patel orders the Army to move into Hyderabad to integrate it with the Indian Union.

Operation Polo was the code name of the Hyderabad "police action" in September 1948, by the then newly independent Dominion of India against Hyderabad State. It was a military operation in which the Indian Armed Forces invaded the Nizam-ruled princely state, annexing it into the Indian Union.At the time of Partition in 1947, the princely states of India, who in principle had self-government within their own territories, were subject to subsidiary alliances with the British, giving them control of their external relations. With the Indian Independence Act 1947, the British abandoned all such alliances, leaving the states with the option of opting for full independence. However, by 1948 almost all had acceded to either India or Pakistan. One major exception was that of the wealthiest and most powerful principality, Hyderabad, where the Nizam, Mir Osman Ali Khan, Asaf Jah VII, a Muslim ruler who presided over a largely Hindu population, chose independence and hoped to maintain this with an irregular army.:224 The Nizam was also beset by the Telangana rebellion, which he was unable to subjugate.:224In November 1947, Hyderabad signed a standstill agreement with the Dominion of India, continuing all previous arrangements except for the stationing of Indian troops in the state. Claiming that it feared the establishment of a Communist state in Hyderabad, India invaded the state in September of 1948, following a crippling economic blockade, and multiple attempts at destabilizing the state through railway disruptions, the bombing of government buildings, and raids on border villages. Subsequently, the Nizam signed an instrument of accession, joining India.The operation led to massive violence on communal lines, at times perpetrated by the Indian Army. The Sunderlal Committee, appointed by Indian prime minister Jawaharlal Nehru, concluded that between 30,000-40,000 people had died in total in the state, in a report which was not released until 2013. Other responsible observers estimated the number of deaths to be 200,000 or higher.

Vallabhbhai Jhaverbhai Patel (Gujarati: [ʋəlːəbːʰɑi dʒʰəʋeɾbʰɑi pəʈel]; pə-TEL; 31 October 1875 – 15 December 1950), endeared as Sardar, was an Indian statesman. He served as the first deputy Prime Minister of India from 1947 to 1950. He was a barrister and a senior leader of the Indian National Congress, who played a leading role in the country's struggle for independence, guiding its integration into a united, independent nation. He was one of the conservative members of the Indian National Congress. In India and elsewhere, he was often called Sardar, meaning "chief" in Hindi, Urdu, and Persian. He acted as the Home Minister during the political integration of India and the Indo-Pakistani War of 1947.Patel was born in Nadiad, Kheda district, and raised in the countryside of the state of Gujarat. He was a successful lawyer. One of Mahatma Gandhi's earliest political lieutenants, he organised peasants from Kheda, Borsad, and Bardoli in Gujarat in non-violent civil disobedience against the British Raj, becoming one of the most influential leaders in Gujarat. He was appointed as the 49th President of Indian National Congress, organising the party for elections in 1934 and 1937 while promoting the Quit India Movement.

As the first Home Minister and Deputy Prime Minister of India, Patel organised relief efforts for partition refugees fleeing to Punjab and Delhi from Pakistan and worked to restore peace. He led the task of forging a united India, successfully integrating into the newly independent nation those British colonial provinces that formed the Dominion of India. Besides those provinces that had been under direct British rule, approximately 565 self-governing princely states had been released from British suzerainty by the Indian Independence Act of 1947. Patel persuaded almost every princely state to accede to India. His commitment to national integration in the newly independent country was total and uncompromising, earning him the sobriquet "Iron Man of India". He is also remembered as the "patron saint of India's civil servants" for having established the modern All India Services system. He is also called the "Unifier of India". The Statue of Unity, the world's tallest statue, was dedicated to him on 31 October 2018 and is approximately 182 metres (597 ft) in height.