Hannah Martin opened the scoring in the first minute and doubled her tally with a backhand shot in the second quarter.
Sharmila Devi pulled a goal back for India but Lily Owsley netted from close range to restore Britain’s cushion.
In the closing stages Grace Balsdon stepped up to convert a penalty stroke into the top left corner.
The victory temporarily moved Britain into second in the pool but they have now moved down into third following Germany’s 4-2 win over Ireland.
Lisa Altenburg scored twice with Cecile Pieper grabbing the other as the Germans built a commanding lead in the match.
Elena Tice pulled one back in the third quarter and Hannah McLoughlin fired past Germany goal-keeper Julia Sonntag to give Ireland hope in the final minutes.
However, Germany were too strong and Franzisca Hauke added a fourth before the final buzzer – despite a lengthy video review where Ireland claimed keeper Ayeisha McFerran was obstructed in the build-up.
The defeat sees Ireland stay fourth in pool ‘A’, while Germany are now level with leaders the Netherlands on nine points.
Great Britain’s Tokyo 2020 campaign got off to a poor start last Sunday with a 2-1 defeat against Germany.
The Rio 2016 Gold Medallists got themselves back on track with a 4-1 win against South Africa.
They face the Netherlands on Thursday while Ireland will play India on Friday.