Cracks noticed on pillars there were speculated by workers as the reason for the accident. However investigations so far have pointed to a design or construction material inefficiency.

While residents in Noida have expressed fear that DMRC is in a hurry to conduct trial runs on the nearly finished stretch, the company said that surface cracks in concrete structures are not uncommon and trials are likely to continue along with the investigation.

'There is no need for panic in the matter. In fact, Indian standard codes for design of reinforced concrete structures allows and permits tension cracks within limits,' a DMRC statement said.

To further investigation, ultrasonic and rebound hammer testing will carried out to check the integrity and quality of the concrete. In addition,

'DMRC will get load testing done wherever considered necessary,' Dayal said.

'Similar testing was done during phase I of the construction also as a precautionary measure whenever required.'