Complex sentence: The project was first envisioned by the Chief of Naval Staff Admiral Oscar Stanley Dawson during the 1980s, but not adopted until 1999, when the Indian Defence Minister, George Fernandes, spearheaded a new drive to realise the project.
Split into simpler sentences: The project was first envisioned by the Chief of Naval Staff Admiral Oscar Stanley Dawson during the 1980s. However, the initiative was adopted in 1999, under the tenure of Defence Minister, George Fernandes, who spearheaded a new drive to realise the project.