Government repression increased in Goa when Portugal came under the military dictatorship of Dr. Salazar in 1920s during which time the modern Goan liberation movement began. Some Goan Nationalists formed the Goa congress Committee in Bombay in 1928. It was headed by Dr. T.B. Cunha who is now regarded as the Father of Goan Nationalism and was affiliated to the Indian National congress.
Nothing much happened for the following two decades. Then Dr. Ram Manohar Lohia, a prominent Indian socialist leader arrived in Goa in 1946 to defy the Portuguese ban on civil liberties. Ignoring Portuguese threats, on June 18 at a public meeting at Margao, he launched a mass movement for civil liberties. However thousands of Goans assembled there had to be addressed by local leaders as he was arrested before he could start his speech. The people however were galvanized with revolutionary fervor. (Panaji's prime shopping street is now called the '18th June Road' in remembrance of this day). The movement that continued till November 1946 died down due to government repression after that.
Guerrilla raids were carried out on the Portuguese forces by Azad Gomantak Dal, a revolutionary group. Emphasis on peaceful diplomatic offensive rather than tough military action by Indian Prime Minister Nehru delayed the liberation that the Goans thought they would get, with India getting freedom in 1947.
In protest by the Indian government, the Indian mission in Portugal in 1953 was withdrawn. Under Dr. Cunha a Goa Action Committee was formed the same year to coordinate the efforts of various groups working for Goa's freedom and to offer Satyagraha (non-violent protest). In response, a large number of white and African were moved to Goa by the Portuguese government.
In 1954, without a fight the Portuguese colonies of Dadar and Nagar Haveli (now in Gujarat) were liberated by Goan freedom fighters. A small group of Satyagrahis that entered Goa that year on August 15 were badly beaten up by the police.
In 1955 the police opened fire killing many satyagrahis, when 600 tried to enter Goa from Patradevi on the north Goan border. (At Patradevi a memorial to the martyrs exists now). The Indian public was outraged due to these developments on both Nehru's dithering on military action and at the Portuguese excesses.
Nothing much happened between 1555 and 1961 as the pressure on the Portuguese was eased because non-Goan freedom fighters were banned by the Indian PM from entering Goa. Due to Pakistani assistance to the colonial government in 1955, an economic blockade of Goa by India failed.
Finally Nehru yielded to public pressure after 14 years of India's Independence. In late November 1961, the decision was taken to liberate Goa by taking military action. This task was entrusted to the Indian army's southern command and in Belgam it began to concentrate troops. The overall command of the operation was given to Major General K.P. Candeth of 17th infantry Division. On the night of 17 - 18 December 1961 the Indian army entered Goa under 'Operation Vijay'.
Making the main thrust into Goa from north and east was the plan along with a diversionary thrust from the south. The wireless and radio station at Bambolim as well as the Dabolim airfield was bombed and destroyed by the Indian air force. Several army units from all sides moved into Goa. The Indian Flag was unfurled on the morning of December 19 by The Indian troops of the 2nd Sikh Light Infantry who occupied the Secretariat building in Panaji.
At the army camp at Vasco a formal surrender was accepted of the Portuguese army. Gen. Commander in chief of the Portuguese armed forces in Goa, Vassalo e Silva signed the document that was accepted by Brigadier K.S. Dhillon of the Indian Army.
Major S.S. Sidhu of 7th Cavalry and one of his officers who died in an attempt to rescue Goan nationalist prisoners by storming the Fort Aguada was a high level casualty on the Indian side. When their unit arrived the next day with heavier weapons, the fort was captured.
Operation Vijay apart from this spread over only 40 hours was swift and almost bloodless and what 14 years of 'diplomatic offensive' couldn't achieve, it achieved. Thus, the 450 year long Portuguese occupation of Goa finally ended.