What would happen if the gravity on earth decreases by a small about?

a loss of gravity on earth would stop pulling down the air, water and earth's atmosphere

ther would be a sudden and significant loss of air pressure

the lack of any forceful gravitational pull would turn humans

Without gravity, humans and other objects would become weightless.

If the gravity decreases on the earth, we will be weightless and pressure will be less exerting on us and we will be able fly