There is an area in Canada with less gravity than the rest of the Earth!In the 1960s, scientists began to chart Earth’s gravitational fields. You would expect that gravity be the same across the world. It’s not like you feel incredibly heavy in the United States while you practically float around in South America. You always feel the same gravitational pull.
However, they found that gravity actually did vary. In Canada, there are certain areas with less gravity than normal. The Hudson Bay, for example, is “missing” gravity.
There are two theories as to why this may be true. One theory cites convection as the cause. Convection pulls the Earth’s plates downward, which decreases the mass in that area and decreases the gravity. The other theory cites the Laurentide Ice Sheet as the cause. The Ice Sheet melted 10,000 years ago and left a huge indent in the Earth, which could mess with the gravity.
Magnetic Hill (India)
I presume, by the way, that the vague term "gravity" actually means "the acceleration of gravity at a constant radial distance from the center of the Earth" (roughly the altitude of the satellite[s] that took the data).
So... why near India?
I don't know, and I wonder if anyone else does. This is not my field, so I am free to make ignorant guesses:
First, I understand that India used to be a separate continental plate; it drifted North and rammed into Asia, thrusting up the Himalayas. Perhaps this collision lowered the effective density in the neighborhood, although I can't see how.
Second, maybe that's where the Moon was gouged out of the Earth long ago and it still hasn't recovered completely. Somehow that seems unlikely too -- it's been quite a while! Before Pangea, even, I think.
This is why the gravity at some places is stronger than other places.