Navi Mumbai? What is the society status of people here?

There is no reason for you fear being mugged in Navi Mumbai. There are hardly any slums there. Buying a house in some places in Navi Mumbai can be very costly. Navi Mumbai consists of mainly middle class and high class people(in terms of money). It depends on which part of Navi Mumbai you are going to visit. Don't wear short clothes, don't wear too much gold, and don't stay out late at night. These are the general rules of safety for any traveller in any country. There is nothing to worry unless you go asking for trouble. I don't think there are any tourist destinations in Navi Mumbai. You could visit malls or take a drive on the roads adjacent to the water bodies.