Actually, the Indians almost surely got zero from China or from Indochina.
The Chinese had arrived at a system of writing digits in a grid, with different columns implicitly corresponding to count of units, tens of units, hundreds of units, &c. When a count was nothing, that cell was left empty. Someone realized that the grid itself didn't have to be drawn, except for the boxes of the empty cells. And, over time, the empty boxes were drawn in increasingly simple form, eventually becoming like circles.
Simplified to circles or not, the empty boxes, drawn without the rest of the grid, were zeroes.
(Still earlier, Babylonian astronomers had a zero, but it got lost without catching-on more generally. The Greeks would sometimes abbreviate “οὐδέν” [meaning nothing] as ‘Ο’, but didn't treat it as a digit.)