The primary importance of BARC is as a research centre. The BARC and the Indian government has consistently maintained that the reactors are used for this purpose only: Apsara (1956; named by the then Prime Minister of India, Jawaharlal Nehru when he likened the blue Cerenkov radiation to the beauty of the Apsaras), CIRUS (1960; the "Canada-India Reactor" with assistance from the US), the now-defunct ZERLINA (1961; Zero Energy Reactor for Lattice Investigations and Neutron Assay), Purnima I (1972), Purnima II (1984), Dhruva (1985), Purnima III (1990), and KAMINI.