Cars parked in bses transformer

some private cars are parked in BSES transformer of our area .the whole transformer has become a parking ground with a tirpaal to give shades to the cars.the gates are kept locked and keys are in custody of senior BSES officer whose and whose relatives cars are parked there .sparks are acommon scenario in a transformer if any spark reaches cars  abig blast can happen as the whole area  is very congested .i have complained the same to bses and delhi goverment but no result till now as the officer has good nexus.HE gives in writing to the authority that no car will be parked but he keeps the cars .please suggest what legal action i can take