ILLEGAL construction over common area gap& blocked natural light air

We have one backside MIG flat in builder Apartment. The balconies of flats were constructed in such a way (2-3 feet inside the covered area of our apartment while leaving common area gap between our balconies and adjacent plot,so that if any building is constructed in adjacent plot in future,no effect will be on cross ventilation,light,air,lavatory outlet and a.c outlet.This map was properly approved by GDA planned as per GDA bye laws as per our sale deed. Now one bulding is constructed in our adjacent plot having no effect on us much because of proper planning earlier by the common area gap between our balconies and adjacent plot but our upper floor neighbour covered that common area gap illegally without approval by GDA and against the bye laws of GDA ,as soon as adjacent building was constructed and it was in our absence and with this illegal construction our Civic right of natural light ,air,cross ventilation is blocked.how to remove this illegal construction.