Hi, I recently bought a flat in chennai. I am in the 1st floor and the ground floor has changed their building plan. So that their entrance is facing the road and the have also built a compound wall in front covering the UDS area, as like an individual house. All these have happened before our possession. The builder also did it for money. Please find attached the photo which will tell you the scenario.
In the picture the red mark is the UDS where newly wall is built, in the other blocks the same space is used for parking vehicles (marked in yellow line).