Concept:
The Geological Survey of India (GSI) is one of the oldest scientific organizations in India.
It is responsible for geological mapping, mineral exploration, natural hazard studies, and geoscientific research.
Step 1: Know the establishment of GSI.
The Geological Survey of India was established in:
\[
1851
\]
primarily for geological investigations and coal resource exploration.
Thus, statement (A) is correct.
Step 2: Identify the headquarters of GSI.
The headquarters of GSI is located at:
\[
\text{Kolkata}
\]
and not Mumbai.
Therefore, statement (B) is incorrect.
Step 3: Check the training institute location.
A training institute of GSI is located in:
\[
\text{Hyderabad}
\]
Hence, statement (C) is correct.
Step 4: Understand GSI's role in hazard studies.
GSI serves as the nodal agency for:
\[
\text{landslide hazard studies}
\]
in India.
Thus, statement (D) is also correct.
Step 5: Identify the incorrect statement.
Since the headquarters is not located in Mumbai, the incorrect statement is:
\[
\boxed{\text{It's headquarter is at Mumbai}}
\]