Kang Moon-Kweon scored twice for South Korea, while India earned their goal via Malak Singh.
India, down by a goal in the first half, went on to waste six penalty corners in the second half through poor execution and good defending by the Koreans.
The defeat means that India will find it hard to qualify for the final of the six-team tournament considering only the top two teams from the round-robin league will play in the final.
Much was expected from the Indians but they disappointed as they were outplayed in the first half by the Koreans.
India had earlier lost 3-4 to Australia.
In the other match of the day, world champions Australia whipped Pakistan 6-0 to go on top of the points table with Malaysia.