Quantum Gravity is a physical theory incorporating principles of both general relativity and quantum theory. Quantum gravity tries to explain how gravity works on the universe's smallest particles. Quantum Gravity is the theory that describes gravity in the regimes where quantum effects cannot be disregarded.
Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics, and where quantum effects cannot be ignored, such as in the surroundings of black holes or similar compact astrophysical objects where the effects of gravity are strong.