Reaching for the sky: Mukesh Ambani's $1 billion home to tower over 500 ft

Construction firm Leighton is working on the home, expected to be completed by September 2008. Leighton's fees will be about $110 million. Interior design, for which another foreign firm has been contracted in, is extra.

Meanwhile, construction is on in full swing so that the ballroom could at least be completed by this October, in time for Nita Ambani's birthday bash, the source said.

Though the Ambanis are refusing to comment anything on their new house, sources have claimed that it is to be named after the mythical island Antilla.

The family currently live in a 14-storey building, Sea Wind, at Cuffe Parade.

According to the Brihanmumbai Municipal Corporation officials, permission for the helipads has not been granted yet.

"The residential plans were approved three-four years ago. Two levels of basement have also been shown in the proposed project," Sudhir Shinde, deputy engineer at the BMC's building proposals department said.