Rock blasting in the residential area

[sholla]

Hi,
BWSSB and L&T are undertaking new UGD work in our area. As part
of that they are laying 12" UDG pipes in the center of our cross road.
For that they are digging a trench 3-feet wide, about 8-9 feet depth
in the center of the road. There is hard granite in parts of our road
and so everyday evening L&T engineer is blasting these rocks and
in the morning they drill and clear these rocks.

We checked with the engineer, he says these blasts casue fractures
only in about one foot radius around the blasting points. I am
wondering whether these blasts will have any effect on the structures.
The road is about 20 feet wide. Do members have any
inputs on this ?

Thanks
sholla