Protruding grill into common area swimming pool of Apartment

Dear Lawyers Our apartment complex has 75 flats (5 floors) with several common areas for society use. We have a specific flat on the 5th floor that has a metal grill about 15 inches protruding directly into the swimming pool. The owners are residing overseas and they have not let out their flat for a long time. Pigeons have created this area as their home and all its droppings are creating a health hazard to residents using the pool. Pool water is also being recycled annually causing lot of water wasted and and unnecessary expenditure to the residents. The society committee informed them to remove the protruding grill as it is over a common area that also is a concern to another common facility. The owners are not bothered and filed a police compliant when some members approached their guardian when she visited the flat. They are adamant and now threaten with legal action. We have filed a complaint with the GHMC. Is there anything that the society can do to resolve this. What are the municipal, police or legal options to pursue. Warm regards Anand