Window grill case

im from kolkata and staying in a society of 35 flats.my question stands as follows:

my neighbour has placed a grill near his 2ft x 5ft  window (appx dimensions) . the point is he has not placed a box grill but insted placed a grill (almost double the size of his window) below his window attached to our building for placement of the compressors(2 pcs) of his flats Airconditioners. its also placed on the duct of the building which i feel should be illegal. Also, the grill extends upto 1 ft feet in front of my window 5ft x 5ft(appx) which is right next to his window. though this grill is not in front of my window but it is just beneath it . its just an inch away now. i feel its a security threat to my flat and as the compressors make noise and create heat it would add to my discomfort.

please suggest what should be done in such a case and is such a grill legal to be constructed on the buildings wall which is not the regular security box grill. i have mailed and sent a request letter to the owner of this flat but he has not done any good in the past 25 days

thanks

gaurav