I would suggest that you try and collate data each and every society in Mumbai, Navi Mumbai, and Thane.
After which try an SMS campaign with the residents for eg: "Does your society have water logging issue? Is your society safe for your Children?"
Or "According to government regulations, a society needs to be well maintained to avoid disaster and accidents is your society built with proper government approved standards not sure call our experts now"
SMS marketing is not dead people don't know how to use it.Neither is Newspaper marketing. All you need to do is get the right message out. Print Signs and display it nicely on your existing client's walls stating that this society is safe verified and certified by your firm's name.
Make a network with contractors and real estate agents ask them to get you projects and provide them a commission on conversion.
Rainy season should be a piece of cake for you to get clients and hire interns and tell them to go on Marketing Survey in each and every area of a society and get valid information for your firm on whose the society manager? what is his contact number? how old is the society? who maintains it? Are they facing any issue.Tell them to take pictures and share it with you and you can see on the photograph itself who will be your prospects. Not much investment required except for stipend and a good camera(which every phone has now) and as this will a market research project to the students or intern you don't have to worry about whether they will be motivated or not and finally outsource your project to a call centre and ask them to generate leads for you and fix appointments and you just have to go and meet the managers and convert them.
More can be advised but for that i need to get in deep with your business plan all the best.