CIDCO listed 17 sites within 100 km of Mumbai — as far as Igatpuri, Pune and Dahanu — based on availability of levelled terrain, whether the site was part of forestland and the presence of hills obstructing it.
These sites were further judged on distance from Mumbai, coastal regulations, topography, ground transport, social and physical infrastructure. Based on this, Wada, Ansoli, Kinvali, Balegaon, Kalyan and Navi Mumbai were found feasible.
Navi Mumbai selected for being aeronautically perfect — good glide scope for aeroplanes, obstruction-free take-off site. Also, it was the closest — 35 km — from Mumbai.