<P> In 1955 a group of unarmed civilians, the Satyagrahis, demonstrated against Portugal . At least twenty - two of them were killed by Portuguese gunfire . </P> <P> Later the same year, the Satyagrahis took over a fort at Tiracol and hoisted the Indian flag . They were driven away by the Portuguese with a number of casualties . On 1 September 1955, the Indian consulate in Goa was closed; Nehru declared that his government would not tolerate the Portuguese presence in Goa . India then instituted a blockade against Goa, Damão, and Diu in an effort to force a Portuguese departure . Goa was then given its own airline by the Portuguese, the Transportes Aéreos da Índia Portuguesa, to overcome the blockade . </P> <P> India made many requisitions to the Salazar regime of Portugal to grant their Indian colonies independence, but when that failed, on 18 December 1961, Indian troops crossed the border into Goa and "liberated" it . Operation Vijay involved sustained land, sea and air strikes for more than thirty - six hours; it resulted in the unconditional surrender of Portuguese forces on 19 December . A United Nations resolution "condemning" the invasion was proposed by the United States and the United Kingdom in the United Nations Security Council, but would be vetoed by the USSR . The territory of Goa was under military rule for five months . However, the previous civil service was soon restored . Goan voters went to the polls in a referendum and voted to become an autonomous, federally administered territory . Goa was later admitted Indian statehood in 1987 . Goa celebrates "Liberation Day" on 19 December every year, which is also a state holiday . </P>

In which year goa had become a part of india