The Delhi Metro Rail Corporation has decided to strengthen patrolling at stations and inside trains by uniformed security personnel and staffers in plain clothes after a string of viral videos of riders caused controversy in recent weeks, officials said.

The latest video that surfaced on social media purportedly showed a couple kissing while sitting on the floor of a metro coach. It prompted the DMRC appeal to the commuters to "refrain from indulging in such obscene activities".

The DMRC recently wrote to the Delhi Police to strengthen patrolling at stations and inside metro coaches to curb such incidents, sources said.?"In the light of recent videos, the metro is looking to improve security and surveillance by implementing several measures," a senior official said.

"One such measure includes patrolling in trains by uniformed police personnel and plain clothes (DMRC) staff," he said. There are CCTV cameras in coaches on all lines, except on some old trains on line one. CCTVs are being installed in those coaches during the ongoing refurbishment process and also at metro stations to "monitor any objectionable activity", the official said.

"This will help deter threats and inconvenience to passengers, including women," he added. The video of the couple kissing in a metro coach has enraged many social media users who urged the DMRC to take action in the matter. Others questioned the idea of filming the act.

The DMRC has also requested commuters to report such incidents to the "nearest available metro staff/CISF immediately so that appropriate action can be taken". The CISF is tasked with guarding the Delhi Metro premises and responding to any situation inside coaches. A dedicated Delhi Metro Rail Police is also present for any untoward activity.

In April, a video purportedly showing a scantily-clad woman travelling in a Delhi Metro coach went viral on social media, prompting the DMRC to request its commuters to maintain social etiquette.

The DMRC in the past had appealed to the people through its social media handles, to not film videos or make reels by causing inconvenience to fellow riders. The Delhi Metro authority has its own flying squad which is operational every day, another senior official said.