Mumbai: A young man's creative idea of apologising to his girlfriend by plastering a 4km stretch of road with 300 flex banners could land him in trouble with the police and civic authorities.

Pune resident Nilesh Khedekar, a 25-year-old MBA student and director in his family business, put up the posters on Thursday night between Sai Chowk and a housing society in a suburb where his girlfriend lives.

The flexes, big and small, named the woman and carried the message "I am sorry" with two exclamation marks and a heart symbol drawn in red.

"By Friday afternoon, everyone in the area was talking about the mysterious message. We tracked down the printer and from him the man who had placed the order," an officer with Wakad police station said.

Khedekar had apparently taken the help of a friend to get the flexes printed and installed, spending Rs 72,000.

"He told us he had had a tiff with his girlfriend and wanted to apologise to her. She was in Mumbai and when she returned on Friday, he wanted her to see the flexes and forgive him," an officer said.

"He apologised for putting up the billboards and now believes he has hurt his girlfriend and her family even more as everyone in the locality is talking about (his stunt). He has admitted he shouldn't have done it."

The police haven't registered a case and let Khedekar go after questioning him, but his troubles may not be over.

The Pimpri Chinchwad municipal corporation, 18km from Pune, is likely to file a complaint accusing Khedekar of defacing public property by putting up illegal hoardings.