Eighteen piers on three corridors of the Delhi Metro have developed "minor" cracks and the DMRC has kept them under the observation of its engineers as it does not want to take any chances after the July 12 mishap that killed six persons.

The hairline cracks on 18 piers on three corridors of the Delhi Metro which are under-construction were noticed by the DMRC engineers who conducted inspections on all the Metro corridors.

"They found hairline cracks on eight piers of the Central Secretariat-Gurgaon corridor, two piers of the Noida corridor and eight piers of the Central Secretariat-Badarpur line. All appear to be minor in nature," DMRC Chief Public Relations Officer Anuj Dayal said.

After the Zamrudpur incident that claimed six lives when an under-construction bridge collapsed, DMRC began a special drive to re-check all cantilever piers of Phase-II and as part of this exercise Shirish Patel and Associates were appointed to conduct a structural audit.

The consultants were also asked to re-check the design of all these 18 points in detail, apart from overall checking of Phase-II structures.

"DMRC will carry out further corrective action if required and take necessary remedial measures after Shirish Patel and Associates have examined these locations," Dayal said.