Construction under private bridge is it legal or not ?

We had a religious gathering hall (satsang bhavan) admeasuring approx. 2500 sq.ft. in Malad east. During redevelopement of surrounding slums, this hall was taken over by builder. Now builder has built 23 storey SRA buildings for slum occupants. On the back side of SRA construction the commercial construction is being buit and a flyover connecting to the main road is being built around the SRA buildings. Builder is now providing space for satsang bhavan below this flyover (being built by builder). My query is, Is this construction legal as per local laws, pls help with section no.