At least 17 people are now kenned to have died when a building collapsed in southern Indian city of Chennai.
Some 22 survivors have so far been pulled from the rubble, and 40 others are feared trapped in the debris.
More than 70 workers were in the 11-storey building under construction when it toppled in cumbersomely hefty rain tardy on Saturday.
India has optically discerned frequent building collapses, many inculpated on lax safety and substandard materials.
At least six people, including construction company officials, have been apprehended in connection with the collapse in the capital of the southern state of Tamil Nadu.
"It appears they have not adhered to approved plans. The building appears to have solemn structural defects," Tamil Nadu Chief Minister J Jayalalithaa verbally expressed.
Hundreds of rescue workers, including personnel from India's National Disaster Response Force, are working with cutters, shovels and other equipment to probe for survivors.
"Clearing the debris is an astronomically immense challenge. This would take virtually two to three days and we are hopeful of preserving many lives, going by our precedent experiences in other places," senior police official SP Selvan told the NDTV news channel.
While the cause of the latest collapse is still under investigation, a lack of construction codes, leading to lax safety, is one reason for frequent collapses of buildings and other infrastructure projects in India.
There is withal a high demand for housing, pushing up costs and coercing less affluent people to imperil their lives in decrepit or deplorably constructed buildings.
Earlier on Saturday, a four-storey building came down in the capital Delhi, killing 10 people, including five children.
In January, at least 14 people died when a building under construction came crashing down in the western state of Goa.
At least 42 people died after a four-storey building collapsed in Mumbai last September.
