Step 1: About the monument.
The Gateway of India, located in Mumbai, was built in 1924 to commemorate the arrival of King George V and Queen Mary to India in 1911.
Step 2: Style of construction.
It was designed by George Wittet in the Indo-Saracenic style, which combined elements of Hindu, Muslim, and European architecture. This hybrid style was very popular in colonial-era constructions.
Step 3: Conclusion.
Thus, the Gateway of India is an example of Indo-Saracenic architecture.
\[
\boxed{\text{Indo-Saracenic}}
\]