"It is one of the greatest moments in my life today. Because of your blessings, I have been given the honour to be the one who dedicates this amazing statue to the nation," PM Modi said.

The statue depicts Sardar Vallabhbhai Patel, India's first Home Minister, wearing a traditional dhoti and shawl, towering over river Narmada. Iron was collected from all over the country for the statue of Sardar Patel, also known as the Iron Man of India.The statue can withstand severe wind velocity and severe earthquakes.

Online booking to visit the Statue of Unity has opened with a Rs. 350 admission fee for the 153-metre-high observation deck that opens to visitors on November 3.

The statue has been designed by Padma Bhushan-winning sculptor Ram V Sutar and has been built by Larsen and Toubro and the state-run Sardar Sarovar Narmada Nigam Ltd. It took about 250 engineers and 3,400 labourers to construct the statue in 33 months.

The Statue of Unity stands 177 feet higher than the current world's tallest, China's Spring Temple Buddha in the central Henan province.

Local tribal leaders had announced a boycott of the inaugural function citing destruction of natural resources due to the memorial. The Gujarat government said the 185 families moved to make way for the statue had been compensated and given 1,200 acres of new land. Activists said about a dozen of their leaders had been detained before the grand event, news agency AFP reported. Police denied they had made any detentions.

"The statue will remind those who question India's existence, that this nation was, is and will remain eternal," PM Modi said. "This (statue) is a source of unity...with this sentiment we should march...and march with a dream to make the country 'Ek Bharat Shreshtha Bharat' (One India, Superior India)," he said.

The core of the statue is made up of reinforced concrete, but its surface that gives it a distinct design, has been created using 553 bronze panels - each panel has 10 to 15 micro panels. The panels were cast at a foundry in China and imported, which led to Congress chief Rahul Gandhi repeatedly targeting the government, claiming that the statue which will have a 'Made in China' tag.

Mr Gandhi again attacked PM Modi's ambitious project. He described it as ironic that the statue of Sardar Patel is being inaugurated, but "every institution he helped build is being smashed."